I have two of them and think they are a hoot.
They do appear to have a couple of problems, however.
First is the problem with failing to eject properly, resulting is stovepipes and cases getting trapped between the bolt and new round. This is because the ejector is slightly out of alignment and not being in a position to impact the base of the spent case as the extractor pulls it from the barrel. Moving the ejector slightly to impact the spent case fixes the problem.
Second, there is a somewhat common problem of them losing their extractors.
Third, the extractors seem to be getting blown out because of firing out of battery issues with resulting case failure KB. I know of several examples, including my own, where this has happened. In many cases, it is with Remington ammo.
In trying different ammo, I have found that Federal and Winchester bulk packs of ammo from Walmart work very well. Remington bulk ammo, aside from the KB issues, seems to be much less consistent and I would not suggest using it.
On the one gun where this happened, I sent it back to S&W who took care of it just fine. The report back says they brought the gun up to current specs and replaced springs. It has run great since being returned. S&W covered shipping both ways and gave me a new magazine as well.