I picked up a pair of the SC3 GTXs last fall, and have worn them ever since. They are spectacular for infield, and pretty good in the OF. I will say they are a bit hot on warmer days. I might pick up a pair of the regular ones or the fells for the summer.
I've probably got about 40-45 games on them, and the nubs are only just noticeably worn. Some of the outer nubs still have that dot in the middle showing. I bet I'll get another 50 games before I start slipping in the grass. I used to go through a set of studs on my cleats about every 50 games, so this is looking good. The boot of the shoes are hardly worn at all, so I can't imaging that would be why they would need to be replaced.