So, I finally got a Mightly Jazz Expert, after lusting for one for a VERY long time. What a disappointment! The tone was great but the neck was unplayable.
With the neck adjusted dead straight from the 2nd fret and upwards it had a weird kink/backbow from the 1st fret and downwards.. When adjusted for normal relief the bass was 100% unplayable in the 1st fret or open strings, crazy fretbuzz even with very soft playing.
When the truss rod was adjusted to remove this backbow and make the 1st fret/open strings playable the neck had far too much relief, to the point of being unplayable (unless you think 4mm action at the 12th fret is ok).
This was not user error btw. I repair/build guitars for a living and this neck is definitely crooked. It didn't look like something that could be caused by shipping damage, but I find it hard to believe that FGN's quality control is THAT poor??? Maybe the neck has been permanently disfigured by sitting in a warehouse for too long with the neck adjusted for a backbow?? I dunno, probably just a bad piece of wood. It happens sometimes.
One (rather poor) solution here could be to level all the frets EXCEPT the 1st fret to compensate for the crooked neck. But based on some quick mearurements it looks like the frets from 2nd fret and upwards would end up being VERY low to make the 1st fret playable with normal relief. Probably to the point where I would normally have considered a re-fret. Maybe the neck is a candidate for heat/press treatment but that's not something I'm prepared to do on a brand new instrument under warranty. And besides, there's no way of knowing how this neck will behave in the future. It doesn't look very promising.
I can only assume I must have gotten a lemon. I had expected MUCH better from FGN. I have to admit I wasn't really that happy about the general "feel" of the bass either. The body was much bigger/heavier that I thought. I mean, it's ash so I expected it to be on the heavy side, but it is also considerably bigger/bulkier than a classic J-bass. The U-profile neck was also slightly on the chunky side for my taste. It wouldn't have been a problem if the rest of the bass had been great, but unfortunately it isn't. The neck also has some rather severe dead spots, and a somewhat uneven response along the neck. The large ash body made it sound HUGE unplugged, extremely resonant, but it didn't really translate much to the plugged-in tone, which was still very good, but not quite as spectacular as I had hoped based on the HUGE unplugged tone. Not that it matters much, the crooked neck makes it useless.
I guess this one is going back for a refund. I don't think a replacement will be possible. This is the white, passive model that's now discontinued and seemingly out of stock everywhere (and hardly ever in stock anywhere to begin with...). The currently manufactured version of the Mighty J is active, which isn't my thing (and again, it doesn't seem to actually be in stock anywhere...). Of course it can be re-wired passive but with instruments in this price range I expect them to be more or less perfect out of the box.
I've had MUCH better experiences with Fujigen instruments in the past. In my experience they are usually VERY good quality. I guess this one must have been a case of very poor luck.