The MoFi suffers from questionable EQ choices according to many. Some people might be fine with it, but to my mind that severely limits its attractiveness even if it is sourced directly from the original master tapes. (And MoFi only trumpeted the fact that it was sourced from the Original Master Tapes because that was their tagline and branding. It's not that any specific album they decided to reissue had suffered from non-original master tape usage, but rather that all albums that MoFi reissued were themselves guaranteed to use the original master tapes. They didn't make their money by "correcting" bad pressings of albums, but rather by reissuing supposedly audiophile versions of popular good-selling albums whether or not the stock pressings sounded good or bad.)
The UK and US Blue Boxes are the same in that they both use stock UK pressings of the albums. The only exception is the Rarities album, which differs in the US and the UK. These stock pressings sound phenomenal. I believe that early boxes use some of the same stampers as the original pressings, while later copies of the box contain pressings made from lacquers cut around 1972 by Harry T. Moss (HTM). These by all accounts were cut using from the original master tapes, yet without MoFi's questionable EQ choices. The advantage that these pressings have over '60s EMI originals is that they tend to be cleaner and undamaged, and are much cheaper. The advantage over the MoFi box, is again that they don't suffer from boosted lows and highs, and also that they are much cheaper.
The advantage that they (presumably) will have over any 2011 vinyl reissues is that they are analog sourced and cheaper.
If you care about the Beatles on vinyl, you really do owe it to yourself to get a clean Blue Box and check it out for yourself.