Here's My Experiences Thus Far
What sold me on the Jaguar was it's rock sound. The problem with the Jaguar and Jazzmaster apparently is this false bit of trouble caused by the Japanese models not being 100% accurate to the originals.
The first Jaguar I played was a reliced 1963 or 64 model in sunburst. Before I had played it, it had one owner who bought it new in the 60's who had passed away and his estate dropped it off at the music store. Overall, I disagree with all this talk of the Jaguar being a "pokey" or "overly-bright" guitar, a good one made in the 60's is anything but. I had the guitar plugged into a Mesa Boogie Heartbreaker. Clean it was very responsive, and very thick, but retaining higher frequencies a gibson Les Paul does not due to the pickups being single coils.
The reason the Japanese pickups sound "bad" vary. In the case of the Jazzmaster it's because the bobbins are too "deep", meaning the pickup's actual coils are more like a Stratocaster and therefore more focused magnetically and vibration wise on a smaller area making them sound thinner. I've played 3 MIJ Jazzmasters, one with Seymour Duncans, and the difference between the one with the Duncans and the other two was like night and day. The neck position on the 2 others sounded thinner and more strat-like, and the bridge was also rather weak and overly trebly on the same stockers. I've never played a Japanese Jaguar besides mine, which has custom pickups, but I reckon the same problem, differences in pickup construction.
As far as upkeep, if you play the guitar enough, it will require less upkeep I find (as dirt and dust and stuff will work up in the saddle screw holes and make them more resisttant to coming loose as you work that junk into the threads). Since I put on the Allparts Jaguar Bridge I have on my CIJ, I've only had to set it up twice, and currently it has no buzzes, lack of sustain, or any of the problems I hear about. There is a difference I can see between the CIJ and the Allparts bridges though. If I remember right, all the CIJ/MIJ Jaguar/JM bridge saddles I've seen have the same sized groove all across, the Allparts and the original Fender bridges are compensated for the different string sizes. I use 009's on the Allparts bridge, and so far, I have no problems with them sliding over under normal playing, I also counteract the the Low-E from moving even farther by giving it a slight incline to sit on on the low E saddle. My Jaguar is set up with no neck shim, the neck is perfectly flat against the neck slot, the bridge is pretty low, and I really have not had any problems with sustain either. It's only just slightly less than my Jag-Stang, which has sustain like a Les Paul because of the way I set it up.
I pretty much come from the philosophy that both guitars are just as good as the more popular models, it's just few people want to spend quality time once to get a good setup.
As for the distortion arguement. I've noticed most people into Alternative, which these instrumentts are used, and typically use a fuzz pedal. So far with both guitars I've used them through tube amps with high-gain tube overdrive for the most part. The Jazzmaster sounds thicker, almost like a humbucker equipped 25.5" scale strat, except with some slightly rich harmonic overtones due to the bridge design (extra strings ringing in sympathy behind the bridge), and a treble range on them that's pretty much unobtainable on a Humbucker. As for the Jaguar, the Jaguar I played throught eh boogie Had a very vicious bite and sharp attack, but it was in no way shrill, it was very thick and warm, but had a lot of good cut to it, and sounded great for the Metallica stuff I was playing at the time. The scale length I believe actually WARMS the sound up, it's the pickups that make or break the Jaguar from my experience. If the pickups can't help the warmer characteristic of the solidbody guitar's natural sound, then it'll sound shrill and harsh. That's why the advent of the high output humbucker came about, in the 80's, there were a LOT of guitarists using Maple and other dense bodies on their guitars, so they would compensate for the lack of low end in the natural solidbody by putting a high output (10-16K) humbucker in it. Put a humbucker on a shortscale guitar, like a Jag-Stang, or a Jaguar, that's voiced for metal, and you'll see what I mean, an EMG 81 in a Jag-Stang is an almost abnormally rich in bottom end sound, whereas it sounds more balanced in EQ in something with a longer scale and denser wood (like a Fender Stratocaster).
I find, basically, that all problems with any of those two guitars (Jaguar and Jazzmaster) are mostly due to the guitar player and not the guitar, though that could apply to almost any guitar out there, yes, even Strats.
