I have an older Denon receiver (with pre-outs) and recently added an Axiom ADA-1500. I am indeed very pleased with the new amp, as well as my Axiom speakers. You didn't give any details as to your listening preferences or whether you will have a home theatre of just listen to music.
Based on your intent to buy the UMC 200 I will assume that you intend to do at least some HT listening. In this case you will need at least 5 channels of amplification. I have not heard the Emotiva amps but have no reason to believe they would be very noticeably different from the ADA1000. I do think either would be noticeably better than any receiver.
Going with an all-Emotiva package (pre and amp) may have some advantages in addition to any possible price incentive for buying both from Emotiva.
Enjoy your new goodies!