Don't have one myself, but the ones I've held seem to handle nicely, and the reliability of those I've seen on the range appeared to be fine.
A few thoughts . . .
* They're set up to use different magazines - for example in 9mmP, you'll have to decide whether you want to use PX4, 92, or 8000 series mags. (I think adapters are available.)
* In 9mmP, the last time I paged through a manual they recommended against extensive use of +P or +P+ ammo, and they warned against any use of "submachinegun" ammo.
* Not as big a selection of after-market accessories as on AR-pattern rifles, probably because it's an import.
I suspect it would make a nice suppressed SBR once you jumped through the appropriate hoops to do so legally . . . I personally would go for a 9mm because of the better availability of quality mags holding up to 30 rounds.