I own a Bryston 4B-ST and 5B-ST (which is the 3-channel version of the 3B-ST), and highly recommend the Bryston line of equipment. The 4B-ST has more than adequate power to drive your Maggies -- it is rated at 250 wpc, but typically produces 290-300 wpc. The Bryston 4B-ST is very clean, dynamic, and leans slightly toward the "cool" side of perfect neutrality -- no tube warmth here -- and it does a superb job with bass control. The 3B-ST is also an excellent amp, and many reviewers regard it as the best medium-powered amp that Bryston makes. The 3B-ST is rated at 120 wpc, but typically produces 150 wpc. Both amps are good enough to reveal any upstream weaknesses in your system. I have not had the chance to audition the Musical Fidelity amp, and thus cannot make a valid comparison.
If your budget will allow, I suggest buying the 4B-ST. It's a fine amp, and has an industry-leading, 20-year transferrable warranty backed by the finest customer service among high-end audio manufacturers. You can buy the 4B-ST for about $1600-1700 used, or you can buy it discounted from the dealer where I bought my 4B-ST. The dealer is "Bestofdeal", a clicks-and-mortar operation in Santa Clara, CA (look for his small ad in the back pages on Stereophile magazine). The owner is Danny Oovlin, and the easiest way to contact him initially is by E-mail at: firstname.lastname@example.org.