Re: Should I buy...
You kidding? I recorded 16 Polygamy Boys & Sneak-Thief records with the RS7000 and had no trouble ever getting great drums out of it, be it with internal sounds or my own samples. As for the ESX1, I played a night with the Hacker where he slaughtered the dancefloor with nothing but that, a 303 and a roland delay pedal.
With all due respect, I think you need to learn how to mix better. Start by giving your drums more room in the track, reserve some frequencies around the fundamental harmonics of each drum sound, put a hi-pass filter of your basslines to let your kick breathe, arrange your melodies as counterpoint to the percussion, etc.
@Sneakthief: can I elect this reply of yours as "post of the century"? no better words could be said...
@lorensteele
If you like bad mixing, then this means you understand already that the secret is in the mix and not in the device you use.
Even a Casio keyboard for kids (that normally sounds ugly) can be mixed in a way that it sounds great...
The instruments you mentioned have all their own potential, so start studying and experimenting, there is no "ready made
recipe" when it comes down to the fine art of recording and mixing. It's all experience, experience, experience.