My personal feeling, based upon real experience, is that the full-length guide rod (FLGR) does not add enough accuracy to make up for the difficulties it causes in the field-stripping process.
The M1911 was designed to field strip, and to detail strip too, without recourse to any—any—tools. Nope, not even one. In the actual field, as differentiated from at the range (no matter how primitive), this can become an important issue.
In my own experience, I have found that a FLGR enhances accuracy mostly because it adds some weight to the front end of the pistol. Up-front weight helps stability, which adds to accuracy.
All that having been said, I must add (in all honesty) that I own one 1911, a shortie, with a FLGR. It needs that FLGR because of the recoil-spring assortment that the rod assembles usefully: Shorties are notorious for needing exotic recoil-spring assemblies to make them work reliably.
But this pistol is a concealed-carry gun, not one I'd have with me in the field. It only gets stripped on our kitchen table, under well-controlled conditions.
Further, I have to note that if the gunsmith delivered to me a pistol that had been tuned for proven competition accuracy, and if that pistol contains a FLGR, then that pistol will retain its FLGR.
I am neither a pistol designer nor an engineer. (Yeah, I can do algebra, including some quadratics, but don't get me started about my frustrations with calculus.) I tend to trust gunsmiths who have shown me that they can do good work.
With the exception of that shortie, I don't want any FLGRs. I worship exclusively at the Shrine to John Moses Browning, and I am faithful to my God.
He didn't use FLGRs, so neither will I. So help me John!