i can only speak about my japanese squier jazz. it is an old 1982 first series squier known as JV, it's a jazz bass 62 reissue. the bass is a lot better than mexi. for me it's better than MIA too. it was very close to the MIA 62 reissue. the bass is light with a resonant basswood body and the neck is wonderful. i'm in love with it!
I own 2 Fender MIJITSO 62 reissue Jazz basses. They are affectionately dubbed the "Twins" cuz they are matching fretted and fretless models. The fretless is a 1996 issue, the fretted a 1989 vintage. These instruments are (very) high quality with nothing about their workmanship to distinguish them from an American version. Necks that are so sweet you'll want to hit your granny! The bodies are poplar. I believe MIJ's to be one of the better buys on the used market. But this is changing as we speak. Their selling price has been steadily climbing for the past 2 years and, though they won't ever have the value of the American versions, they are a pretty good bargain today. As such, they are also a great platform for customization! You won't devalue the bass much and, as far as my experience, they accept all American hardware without modification except the tuners. I got the fretless in a pawnshop for $299 and the fretted from ebay for $275. Even if you add all of the expense I've incurred for the customizing, it won't add up to half of an American Deluxe. That's the value!!
When I bought my MIJ Geddy Lee Jazz, I had looked all over the Dallas/Fort Worth area for a Jazz bass that would make me happy. I played 40-50 MIMs and at least 20 MIA(the American Standards, back before the American Series came out) and couldn't find one that pleased me both soundwise and construction wise. I walked into a local shop and saw this beautiful tuxedo finish Jazz, maple with black blocks like I have craved for years, plugged it in and played it, it passed that test, looked at the fit & finish and it was as good as any of the MIA's I had played, so I bought it. I didn't find out until after I fell in love with it that it was a Geddy Lee signature. I would have bought it even if it wasn't, but that cinched the deal. Here's an obligatory pic of mine. <img src="http://albums.photopoint.com/j/View?u=994952&a=7315325&p=24853843&Sequence=0">
The ones I've tried are on par with the US Fenders in terms of quality. That could change, though. All those cellphone recalls, the Firestone blowouts, etc. etc. You know.
Ive got both MIM and MIA's(a P&J of each),and imo the MIA's are built a little nicer than the MIM's.They(MIA's) seem to have nicer hardware,electronics,and the fit and finish seems to be a notch above the MIM's. However,imo the MIM's are the best bang for the buck,and with a few inexpensive upgrades can be made into a top notch Bass. I wouldnt give up either of my MIM's. As far as the MIJ's,the only one I had was a Geddy,and I didnt care for it. As always,YMMV.