I had an Affinity P. It definitely sounds and plays like a P-Bass. I can't really imagine a gig that it couldn't handle that a Fender P-Bass could. That said, if you like to tinker a bit, or find inexpensive solutions for various deficiencies, it'll be a wiser investment than if you just want to play.
The tuners were ugly but did keep it in tune. The electronics were weak, but the pickup was fine. I didn't love the bridge, but I never got around to replacing it, and it didn't fail in any noticeable way. It was very easy to play. It felt a bit cheap, but not in a way that inhibited playing.
If you like to tinker with stuff a bit, it's a great option. If not, it's worth bumping up to a Vintage Modified or Classic Vibe bass, because you'll have something that's not gonna need much tinkering. My Vintage Modified Mustang Bass is stock. My Classic Vibe Strat was pretty amazing right off the shelf, and though I've modified it, I wish I hadn't.