I haven't had much time shooting either (just passing around shotguns while skeet shooting and such) but when an 11-87 (3.5") came up for grabs for a great price to me I did some research on it. Apparently it is complete garbage on every review i could find. It does only apply to the 3.5" though. The others sometimes eat O-rings quickly too.
The Sx3 is a nice light feeling autoloader. (no research done at all) Out of the two (and based on my little experience with both) I'd recommend that.
Here is some first-hand research for you: I put approximately 10K skeet rounds through an 11-87 one shooting season. I replaced an o-ring (total cost $0.60) at the end of the summer, although it was still operating fine with the o-ring that came with it.
True, there are more modern designs, and I prefer to shoot several other semi's (notably Beretta 39x series), but I certainly wouldn't call an 11-87 "complete garbage". They are still a great-handling, fairly reliable semi.