Tuner,
Well I really can't speak too much about the round followers in the .45 mags. By the time I moved away from the Wilson 8 rounders, Jim had my 9x23/38 Super done. I've only got about 3,000 rounds through my .45 ACP chambered 1911s with those round follower Metalforms. That's really not enough to notice any problems that might surface using them.
If I had to take a guess, I've probably got about 10k now in 38 Super through the gun using those mags with the round followers installed. Jim liked the Wilson follower because it allowed 10 rounds in the magazine, but after I wore them all out I got one of each of the different 38 Super followers Metalform offered and tried them all. I just liked how the round follower worked the best. Although it only allows 9 in the mag, I figured 9 was good enough.