Reply to CDJ/Mixer questions

I'll try and be clear about these questions:

1. Was messing around with my friend's CDJ 400s and really liked the WAH effect. Is this effect only limited to the CDJ 400?
2. The roll effect on the DJM 400 isn't the easiest tool to use, at least for me. Are there any mixers out there where the roll/loop effect work fantastic and are very responsive? I know I need to just practice, but I'd like to know for future upgrades. I really miss the accuracy of looping on the S4.
3. I really dig filter effects. What are some great, if any, intermediate/affordable mixers with exceptional filtering? Found a Xone 92 for 700, but haven't heard back from the seller, so I'm sure I'll never see that price again for that mixer.

Thanks in advance.