Incorrect waveform displays (so much for that big and differentiating feature)
Relatively hit or miss looping (don't flip it up for a millisecond)
Both points have been brought up 2 years ago. Functionality, nothing has been done for the 850 - albeit a new color has been released every year, but that's about it.
Anything else? Oh, your suggestions, concerns, and issues will be merely 'forwarded to the engineers'. 2 years is a long time to get a straight answer from both the forum moderators and engineers. Second doubts? Yes.
Btw, those are the 850's TWO standout features and they are both fLiMsY