I'm not sure that there is a consensus that the Army GME is "tops." Having trained and worked in both AF and Army GME, I see exactly the same problems with both. The Army does, however, have the largest GME program and the best chance of going through without interruption for GMO time.
It's hard to generalize about AF GME, but overall, highly specialized, procedure-heavy programs have the biggest problems. Once Wilford Hall closes, the AF will have no medical centers that are the equivalent of a large community or university teaching hospital—hard to generate a high volume of complex cases at a small hospital. But the situation is also complicated by the fact that some AF programs have essentially closed and been folded into nearby civilian programs, so quality is essentially dependent on the civilian institution, for better or worse (usually better).
No residency program is "bad" since they are all (with the possible exception of Keesler) ACGME approved. You will likely end up as a competent physician if you train in the AF. But a better question to ask might be this: How would an average student rank the Air Force programs if they were in the same match with civilian programs? For many specialties, AF programs are relatively low volume, not big name, with transient faculty, poor ancillary support, multiple off-site rotations, and unattractive locales. I think it's a safe bet that these programs would rank near the bottom of everyone's list. So it's not that they are bad programs per se, but they would be much less attractive to most top-notch American grads. If forced to compete with civilian institutions, they would attract only bottom-tier American grads and FMG's.
That's why there are many students coming to this forum with the question, "How do I get a deferment?". It's because for a top-notch student, there are civilian programs in virtually every specialty with a lot more to offer.