I've got 2 Mustangs, a PJ and a JMJ and they are very different basses.
I've had my PJ wired with a blend pot as I found the stock 3 way pickup selector switch was too limiting, the blend makes the bass much more versatile as you'd expect. The pickups are clear sounding and work really well together and give a range of familiar Fender tones from the trademark P grunt to that wiry bridge pickup sound. My favourite setting with the blend is just off centre with a bias towards the P pickup which gives a full but clear tone that sits nicely in the mix. The neck is a slim, jazz like profile.
The JMJ is different in almost every way. The custom Seymore Duncan pickup has a big, full tone with less top end than the PJ, it's very much a fat, rounded vintage tone. It's not as versatile as the PJ but it's got that tone that both works with the band and puts a grin on my face at the same time. The neck has a chunkier profile, feeling more like a Precision profile.
The lovely @Adee had an American Performer Mustang that I was fortunate to have a ply with before lockdown. It's more like the PJ than the JMJ but with higher grade hardware and a more pleasing neck finish than the PJ. But that's not to say the PJ has crap hardware or a poor neck finish, as it doesn't. But the pickups on the American model sounded a bit bland to my ears, they lacked the character of the PJ and the JMJ.
Out of the bunch I felt the American was the weakest model simply because the tone was the least exciting to my ears, not a bad sound as such, just nothing that grabbed me. And it's also around a grand or so. As the PJ and JMJ are very different basses they both have their appeal and I'll pick up one over the other depending on my mood. But the following day I'll happily play the other. I like them both a lot. There's also the Vintera and new Squier models but I've played neither one so can't comment as to how they compare.