I estimate the Ascend would have a lot more depth and bass over the Q300's. I read some really bad reviews about the Q100's when I was considering them and I went with Monitor Audio RX-1's instead. I'd imagine Magnepan's are different, not an entirely different level, but just much different. I feel like bass would be an issue with them too.
Paradigm Signatures, Monitor Audio, Swan, and Dana would probably be on my list before Magnepan.
This is a review on the Magnepan's and I think it is probably what they'd deliver to you.
You will have a love/hate relationship with these speakers if you choose to buy them. You will be absolutely astounded by the way some music sounds on them and other music will sound completely lifeless. Here's what sounds good: drums, acoustic guitar, chamber music, female vocals (particularly stunning). Here's what doesn't sound good: anything with significant bass, including acoustic bass in jazz, bottom two octaves of piano recordings, tuba and percussion in orchestral recordings. Occasionally, you just hear the bassist play a descending line and it completely disappears. Likewise, frequently the left hand of the piano lacks depth. Orchestral recordings The two most egregious genres that I've tried on these speakers are reggae and psybient. You might as well listen to this kind of music through two cans and a string. People say that these are the best speakers under $1000 and I suspect that this is probably true in some respects, but you have to consider the cost of the amplification that is required to drive these speakers adequately, which is quite a bit greater than many comparably-priced speakers. If you like to listen to anything with bass, including orchestral music, jazz, or particularly organ music, you will need to buy a subwoofer, so plan on another grand disappearing right there. By the time you're done buying a high-powered stero amp and a powered subwoofer, it might have been a much better value to buy a pair of full-range floorstanders.