In a back-to-backs for me, it did not compare well in tone or fit/finish with both the G&L Fallout Tribute or the Schecter Banshee. I personally went with the G&L, but you should try them yourself if you can, as these instruments are similar only in scale length (30").
Note: The mustangs I compared were the American Pro model and the JMJ model (MIM). I was unable to find a standard MIM model. I think they backordered for like forever...
That's not really a back to back comparison, to be fair - you can't really compare the tone of a Mustang pickup to a Precision pickup. Those basses won't really sound that similar to a PJ.
I own an MIM PJ, it's my favourite bass to gig at the moment, but there's definitely issues.
I replaced the tuners (weakest hardware part of the original, although they were functional) - I just prefer Hipshots. I also put on a high mass bridge, mainly for aesthetics, but it did help a little with balance. Lighter PJs do have a tendency to neck dive. Also swapped out the 3 way switch, which was crackling very soon after buying the bass.
My main problem with it is the slab body - it's fine, I can play it, it isn't even uncomfortable - I just prefer contours. The Jazz pickup is also a little weak, but I don't use mine.
Now, the good parts - it may have my favourite neck ever. Nice and quick, smooth satin finish, and my tech got the initial setup right where I want it easily. Low action, no buzzing, no fret sprout, and no pronounced dead spot as you'd find on a 34" scale Fender.
The Precision pickup is GREAT - I can't remember the model it's from, maybe someone said a Classic 50s? But either way, I was expecting to change it, and have never really felt the need. I'd only do it now for a tone change rather than an improvement.
The finish on mine is great, fit is great, never a second of worry that it'll let me down at a gig. It sounds like a P in the mix, low end for days, without the 'flabby' sound a short scale bass can sometimes get.
Overall, I'd say try before you buy, or get one from somewhere with a good refund policy. I really, really like mine but I can see there being enough deal breakers for someone to have an issue with it. For me, it's got to be the best bass I've owned in that price range.