I have heard neither ! However I have a MF A3.2 and my previous amp was the MF A3. The MF brand delivers excellent quality from my experience with the two amps I've owned. Both amps you refer to are an upgrade from mine, I'd just go for the one with the most appealing spec for your requirement. If you like the MF house sound, you're unlikely to be disappointed with either.
Just my feelings, you understand.