Tony, I have an MCA-5II paired with an Anthem AVM-20 processor and Paradigm reference series speakers. This combo sounds really, really nice and if the new line is a big improvement I cannot see how you can go wrong. I have heard that it is. Hell, they are about 3" taller in size than the previous series to accomodate the bigger transformers and power supplies. I bet they are great.
I also have an MCA5-II. I'm wondering how well the new ones will match with it when I go 7+ channels later on and get either the new 20 or 30 amp.
I guess I could still grab the old ones used, but they don't pop up all that often on ebay, audioreview, or audiogon, and I'm sure stores won't be selling them much longer.
I have an MCA-30. They cost quite a bit more than the old series amps. The MCA-3 was $900, the MCA-30 was $1200. They are about 2" taller, but that allows much larger heatsinks. This amp stays nice and cool. I'm using Paradigm Studio Reference speakers and it sounds great.