Considering making the switch from Traktor w/ DDJ-SX2... LOTS of questions

Not very enthusiastic. Not from users nor from support it seems...
Personally I would say: devide and rule. Pioneer is an extremely good hardware vendor. In software vending I miss out on experience.
I am by now quite happy with rekordbox for preparation, It didn't start like that when I bought my CDJ900NXS setup being drawn by there 'workflow' and 'seemless' integration.
So: preparing on a tablet never happened because Pioneer is too good to serve Android or Windows Phone OS-es. We, the users, are insufficient in providing them with means to develop.
Preparing on my W10 Laptop and PC with a now working sync manager is really great and gives me about 2/3rd of what I had hoped to buy if it comes down to promised workflows.
With that experience in mind I decided to wait a little before rushing into buying the shiny brand new software product. For that I am still happy with my software vendor that took me from vinyl to digital. And that is not yours. It's the other one. Both very experienced software vendors by the way ;-)

Sorry, we're tackling a huge influx of questions right now... I'll answer what I can from a purely user-opinion perspective:

0) I've found the "crash experience" to vary from user to user, and I'm not sure if it has to do with the computer, or the music loaded into rekordbox, or what ... but I've only had a couple of crashes in all the versions of rekordbox I've run over all the crazy configurations of hardware, and actually TRYING to get things to screw-up. The biggest problems I've ever had were on a Windows PC with a crappy old graphics card.

1) Not using the effects in Traktor often, I can't really speak to a proper comparison.

2) It's decent - there are improvements that could be made, and they're on the engineers' list, but yes, there are intelligent playlists available.

3) Key analysis is pretty on-point!

4) If you're already using an SX2, you won't be able to add another controller at this point. Future updates will allow for easier integration of additional controllers, and a better mapping experience.

5) You should be fine, each update seems to be better with regards to resource consumption.

6) GPU, but you can adjust the redraw options.

7) Compatibility is bang-on. There are a couple of labelling differences between the product and the feature it controls, but that's because it's a controller designed for Serato DJ, not rekordbox.

8) Sounds decent - I'm not a scratch DJ, but I've never found it to be "early 2000's digital" so it works for me.

You can try Rekordbox DJ free for 30 days, load a bunch of tracks in and see how it performs.

I tried Traktor about a year ago and didn't like. Rekordbox DJ to me feels like a CDJ expansion pack so the learning curve was small. I use Rekordbox with an XDJ Aero, not quite the best combo but it works. Rekordbox does crash once in a while but Rekordbox DJ hasn't yet.

Performance wise my 2016 Dell XPS with a Core i7-6700HQ relatively idles. With 4 tracks running I see between 10% to 20% cpu usage. On battery my laptop is good for about 6 hours of web browsing which drops to 3 hours when performing with Rekordbox DJ which I think is quite good. When practicing I like that I don't need to power my laptop. 

I am  long time traktor user but a while back i bought a SX2 and have been using it with Traktor, Serato & RBDJ.

RB DJ has been stable for me.   I use it a a minimum of about 5 to 10 hours a week and have yet to have a crash.    

Im not power effects user but the effects on RBDJ i feel are very similar to Traktor effects.  I still learning RB DJ but i can't figure out how to get a one button echo out like i do with Traktor.  

Mapping with Traktor is far more powerful.  RBDJ seem  limited compared to traktor

Came from Traktor with an S4 and also a separate set up with Traktor using vinyl DVS.

Spent a bit of time in Serato as well but didn't like the way some things worked. Eg. Loop length tied to roll length, slip mode continuing between songs, some effects disorted (echo out).

Rekordbox seems to be the bastard child of Serato and Traktor. Has the best features of both. Initial versions were buddy but current version has been rock stable. It does use a lot of CPU compared to traktor and serato. I use it for 5-10 hours each week and never had a crash. 

Worst thing that has happened on a gig was headphone volume on my DDJ-RZ was attenuated for the channel cues. had to restart rekordbox dj to fix it, but that was pretty much it. It was also about 4 hours into a gig last week..

It has the best library functions out there, it has some excellent pad effects like echo out, roll, spiral, etc. 

Download the demo, plug in your controller or mixer with DVS and try it for a month. Better than asking a highly subjective question. It may fit well with your workflow, it may not.

SKDJ, Pulse, DJ Phil, Troy Michael, Harry J Thank you guys. That's a lot of positive feedback, and I'm amazed at how fast the responses came. Community seems more active here, too, which is another thing I'm looking at. The NI community is pretty much stagnant so questions don't get answered nearly as quick.

All of you mentioned gigging with it and it being very stable; how does it handle corrupt songs? There's a huge uproar in the NI community because Traktor crashes if a song is corrupt, which you may not know until you're mid-set loading it and trying to play. How Rekordbox DJ handle this type of problem? Does it just distort/garble the music, refuse to load a song, clip/skip, etc?

Compared to most DJ my library is like smaller and hence likely in better shape that most but i have never had issue with bad files on Traktor, Serato or RBDJ.   

I believe Serato sometime flags a few tracks as bad but yet i was still able to the same song on all software with no issues.   

I used Traktor for several years, first on an S4, then on a custom mapped DDJ-SX.

I loved the Pioneer hardware over NI's and was super excited when RB-DJ came out. Been using that for a year on the SX.

0: I can't complain about stability. It's never crashed on me but I'm not a power user. I occasionally play out for 1-2h sets or at home.

1: I much prefer RBDJ's effects. It was one of the main reasons I wanted the switch. I always found Traktor's to be either too overbearing, too weak or confusing. RB's sound professional, are always quantized (beats are always controlled with the rightmost knob)  and the FX sound like something one might actually use.

2: Library management was my my second main reason to switch. In RB you can add custom tags to your tracks and then later do a search based on them ("bangin" AND "housey" AND "main hour", "Amin", "125bpm +/- 2%), all through a nice checkbox UI. Or have RB do it's own selection based on preset criteria, or even tracks you've previously tagged as matching eachother. In Traktor I'd try to use iTunes to sort. Or just end up using my latest 200 or so tracks. RB allowed me to find tracks I'd not thought about, or older stuff (if I had tagged them)
RB has hands down the best UI for finding tracks. Yes it also has smart playlists.

3: I use MIK too so not a big deal. I guess key analasys is good, never used it. Beat analasys is great though. Seems to always get the downbeat right. Traktor's is always off by a few beatgrid nudges.

4: Mapping in Traktor was always a PITA but you could do pretty advanced stuff. RB's is very basic still. It needs a huge overhaul and at this moment I wouldn't add anything on that isn't in the Pioneer official list except for some simple on off event triggers.

5: Works fine on my 5 year old i7 lappy but like I said, not a power user.

6: Haven't had any heat problems.

7: Some minor labelling is off but no complaints.

8: I don't scratch

Overall as others have said, try it out. I really like RB DJ but have to admit that I just recently went back to Traktor for one reason: The S8...I wanted to escape laptop face but can't afford a CDJ setup (without sacrificing tons of controller features at least).

I'm currently going through buyer's remorse. I can't believe I lasted that long with Traktor's crappy library management.

On the other hand, I did like coming back to loops that work, hotcues that quantize correctly even if you're a smidge late, the step sequencer and, err...that was it.

Thank you, Arild Anfinnsen! I think that just about wraps up my questions. I just finished a wedding reception gig over the weekend that I spent weeks preparing for because of the brides' requests, and then I only wound up playing a few of their songs as they liked what I had picked instead. Now that THAT'S over, I'm going to give RekordBox DJ a shot. Looking forward to it. The community here seems awesome, as well. Thanks everyone for your replies!

You're always better off managing the bad files before there's a problem (but most people won't find them until they play the song and blammo!) There is no error-checking built-in as there are too many different filetypes and possible errors.