I agree that the BPF filter is a bit loud. The XPAD level acts as a dry/wet control when using ROLL, with 12o'clock 100% wet. When you're playing samples you just drop the XPAD level down to 9/10 o'clock and they'll be a bit less overpowering.
Pulse did a good video regarding setting the levels: http://forums.pioneerdj.com/entries/20183281-how-to-properly-set-levels-on-efx
I find that with the channel levels at 0db and with the Send/Return level at 12 o'clock the the input and output levels on the RMX-1000 are best set around 12o'clock (tweak them whilst turning the send/return on and off so that you can get it just right). With my DJM-700 I can't tell the difference when I turn the send/return on and off in either levels or quality (something I never managed to achieve with my old EFX-1000)