The 3630's are dirt-ass-cheap for a reason. Yes they can make your synths duck your kicks ala Alan Braxe/daftpunk style, and it does come down alot to user skill.. I say grip the 3630 so you can play with it but as for a midrange comp that will suit mpc/beatmaking well check the Focusrite Compounder, they can be had for cheaper (than you might expect) on ebay if you lurk hard enough.. Focusrite makes some decent stuff and its got a bottom end expander thats supposed to be pretty usable. Generally those exciter type features are marketing BS

. The focusrite gets some good reviews and even so by the usual gear haters over on Gearslutz... FWIW i havent used the compounder but thats the next comp on my list.. A caveat here, I DO plan on buying a 3630 of my own so I can pump the fuc!< outta my synths sidechain style and otherwise, then free up a better comp of mine for other more important tasks, I just wouldnt want it as my ONLY comp.
Really if you are OTB then you should be considering several comps (the compounder is two chan).. Really i could easily have a smattering of many different comps across my mixes..
one for..
bass synth/sample tightening
duck the synths under the kick
individual drum tracks/elements
drum buss
vocals
main 'glue' comp for master buss
I bought a symetrix cl150 at a used music gear shop (cheap!) and its kinda an unknown piece but there was a lil internet info on it so i picked it up.. It works nicely as a parallel comp and i can get some really crunchy snares from it as well as abusing its sidechain inputs, point here, take a chance, look locally and see whatt you find..
It doesnt have to be a 1176 or nothing, just aim higher than a 3630...
Another one to look at is the dbx 160a,160x,theyre a lot better than the 266 or 166xls or whatever those cheapy sub $250 new boxes are.. the 160's are classics..
Search gearslutz for compressor topics, A LOT more info on there than mpc-forums...