I don't own one, but know a couple people who do. They like them.
Reliably wise, they either work or are broken. Which is what you want in any gun.
Personally, they're a "Carry a lot, shoot a little". Type of gun. Perfectly fine to shoot, but there are more comfortable options available if you want to put a lot of rounds downrange. (Not gonna list them because I don't want to derail the thread.)
I'm not aware of anything lighter than the Sub, so if you're backpacking with it just in case you need something, I can't think of anything better.