No, I'm not a pro, but I'm not bad either. I used to play local SF3:2I tournaments at a game center in Aichi when I was in Japan in 1997, and I did pretty well...but I learned very quickly that it doesn't take long to find people at a game center who will let you know that you're not that good. I would definitely say I'm above average at SSFIV, and I certainly did my share of reading and contributing over at Shoryuken.com.
As for inputs, I don't judge a game based on how easy or hard the combos are, although I've heard that compared to SSFIV (which, again, has some insanely execution heavy (see: desk) combos) the combos are significantly easier to pull off. I prefer if good decision making is more important than good execution in a fighting game. If I do have any problem(s) with MvC3, ease of execution won't be it.
Brain, you said that in chat as well...but, without playing the game, it looks like there are multiple 100% damage combos (without X-factor) on YouTube already. How practical they are remains to be seen, but my initial impression remains that MvC3 is the kind of game that will be more fun than SSFIV for casual gamers, while SSFIV is the kind of game that will be more fun than MvC3 for people who want to put hundreds of hours into learning the ins and outs of the game, and play at the highest level they can.
I wouldn't mind being proven wrong, and I should be holding a copy of the game in my hands before the end of the work week. I'm glad I'm going into the game with relatively low expectations, either the game is roughly what I'm expecting, and I'll have some fun with friends while it lasts, or it will be better than expected and I'll be pleasantly surprised.