I've had the Sierra 2 for about 2 years but no experience with the MA speakers. What's impressed me most about the Sierra 2 is the level of detail. Vocals, piano, or analog type of instrument sound so realistic and in the room, all without getting bright or harsh.
I'm running them with Parasound Halo gear and I originally bought the Ascends for the theater system, but became so impressed with how they trashed the speakers they replaced(Paradigm Monitor series), that I tried them out in the 2 channel system. To my ear they were the equal of the Paradigm Signature S6, a floorstander with berylium tweeters. Of course they couldn't match the lower octaves, but I preferred the vocal reproduction of the Sierras. The S6 costs at least 3 times what the Sierras do, and this is where I think internet direct companies can offer more value than the traditional wholsale/retail brand.
I would say though that any stand mount speaker in this price range benefits from better quality electronics. Receivers can only do so much.