?

I don't think there's any way to say that one maker or another is going to be more accurate than another because they simply are not made to the tight specifications of match barrels which allows variation from barrel to barrel.  You should be able to expect 2MOA or better from any of them and you might get lucky and find one that will do sub MOA.

If you want to -know- that the barrel will be accurate then you need to look for a stainless match barrel, not a chrome lined barrel.

I don't know,

but Wilson's Combat is good, and Barrett's can't be bad either.

Quoted: I don't know, but Wilson's Combat is good, and Barrett's can't be bad either.

Wislon Combat doesn't have chrome lined barrels.  In fact, I don't think they even machine their own barrels, much less make them. I would guess that they get their barrels from Wilson Arms or some other barrel house, or is Wilson Arms who you meant?  The only AR barrel that I've heard of from Barret is on their 6.8.  Is that even for sale yet?