The TRB1005Js are nothing more than the TRB-1005 made in Japan, as opposed to Korea (early runs) or Indonesia (later). Same pattern, same woods, same pickups, same preamp. The one thing that differs is that they are available in a trans blue quilt, which is not found in MIK and MII models. That, and the fact that even used ones trade for about double the price just because they're MIJ.
Build quality, playability, aesthetics, all top-notch. The early 2000s styling - "Nathan East era" - coming from Yamaha in their BB and TRB lines was right up my alley. The TRBs are bigger-bodied than the BBs, which balances a 5-string neck that much better. I've not yet met a Yamaha that didn't play like butter with a knowledgeable setup performed, which is much more than I can say for many other makes. The tone and natural EQ are a little flatter than your average bass, owing to the low-output hum-cancelling pickups. That's something to keep in mind; the bass was voiced for modern jazz and fusion, so you'll get more high-mids and highs out of it than your average passive dual-pickup or even other actives. While you can dial it back to more vintagey pop-rock tones, in my experience it takes more than the onboard treble control to do it. Just keep The Complete Instrument in mind when tone-hunting with this bass, and it will do a lot for you.
Downsides? There are a few. The neck is bolt-on (a through-neck TRB will set you back at least $2500 for a good used TRB5PII), and 6-bolt to boot. Very stable, but access to the higher frets can be trickier. Usually not a problem for me any way you slice it, but I did have an Ibanez BTB that did a better job with high-fret access (unfortunately there were other problems, so I passed it on for something that does what I usually do better). The electronics also have some drawbacks. The low-output coils are individually buffered by the preamp, before their signals are combined with a trimpot to vary the amount of noise cancellation/humbucker tone. The advantage is that if you want an even clearer single-coil tone with more personality, it's available by turning down the trims. The disadvantage is the hum-cancelling is never perfect, and the board is a known power hog owing to the multiple gain and buffer stages in the circuit. My TRB's good for maybe 80 hours plugged-in time off a fresh Duracell, which isn't terrible, however other preamps have been logged at hundreds of hours off one battery. One of the more common mods to these TRBs is an electronics swap for Bartolini P2 soaps and an NTMB preamp to solve both problems. Myself, I lined the pickup wells with copper tape, tweaked the wiring to short the main and phantom coils of each pickup, then turned the trimpots to minimum. That cut the noise considerably (you're basically taking two of the voltage buffers out of the circuit, plus the shielding), of course I don't have variable coil adjustment anymore, but I never really used it anyway, and the mod is easy enough to reverse.