@Dr. Cheese,
Hopefully this is still relevant. I just purchased a XJ-1T (4 string). Here are my own thoughts after having it for a week.
Build quality is excellent, paint was flawless (nicely done transparent creamy yellow over the Ash body) and the oil finish on the neck is terrific and seems thin - easy to really
feel the wood. Maple neck and fretboard is of one piece of maple. Frets are done well too. Eventual fret sprout is likely in dry Colorado, but I'll deal with that when/if it happens - then re-oil the neck if/as needed after the frets are re-dressed.
I'm primarily a finger style player and can slap a bit but I'm not great at it. Finger style sound deep, full, warm and bell like in the highs. Slap is crisp and defined. EQ lets the player tailor the finger or slap sound to suit their tastes.
The neck is thin and not wide - again, feels like a J-Bass. The wooden pickup covers are a nice touch. Top of the pickup cover is chamfered as a thumb rest if you're a non-floating thumb player. The neck heel is also slanted just a bit to make the the higher frets more accessible - nice touch and without a neck plate too.
Bass came with very low action - I raised it a bit and set intonation after installing new strings. Pre
is musical and bass is silent (no hum/buzz) hands on or off the strings.
Mid and treble switches work well - mid switch especially - easily adds low-mid punch when set that way. I set the active level to match passive as it came a bit higher when in active mode (adjustment is under the rear cover). Watch out when adding too much bass/mid/treble on the active pre and using the switches. It's easy to overload your amp's pre input.
Passive mode is
very nice too. Clean and deep with sparkly J-Bass highs. Boosting the treble and using the treble switches at 6 kHz
can make the treble a bit honky to my own ears. I pretty much leave the treble switch at 12 Khz and dim the treble on the pre or the main treble control when in active mode. That brings the string brightness down a bit, but keeps the sparkly highs present.
Still working with the Pre Mid control though. I like it best with it dimmed ~10-15% from the center detent. If I boost the Mids, I'll dial back the Pre Bass control and keep the Treble dimmed too.
IMHO, the front pickup is warm, but not P-Bass Mids warm - but changing the switch to 400 Hz and adding some Mids gets it close. Yes, it's got tons of deep tones in passive mode too - and the balance control dialed to the neck pickup keeps the bass warm and P-Bass (ish). It's even better (and with more control) when in active mode and dialing in the switches and/or using the active pre controls - again, it gets very close - but I already have a P-Bass with flats for those tones so it's a bit irrelevant.
The down side is that IMHO, the rear pickup doesn't really get that barky /burpy J-Bass bridge pickup tone - more nice warmth and clear tone than barky/burpy. I'm still working with it though to figure it out. It "may" be in there, but I haven't been able to dial it up yet.
Frankly, it sounds and feels like a very high quality Jazz bass - think Sadowsky level quality. Quiet for the studio - and not affected much in EMI/RFI heavy environments. In my own music room, all of my other basses hum - this one is dead silent.
The only other ding that I can find is that there isn't a separate battery compartment. IMHO there should be one as changing the battery requires a screwdriver and shouldn't.
Look, IMHO this bass tends towards more of a 70's Jazz Bass tonality when set flat, but I can dial it up to a 60's tone or darn close to a P-Bass tone too. If I had only one bass to carry in my bass quiver, I'd likely choose this bass due to it's great versatility - and doing all of the tones that I need well. For me, there are times that a Precision with flats just can't cover the tunes that I play. Can't say how this one would sound with flats as that's not it's job. But if I only had one bass, I wouldn't feel queasy in stringing this one up with flats and playing just about everything I currently play with it. Good to know that I don't have to either.
Lastly, I changed out the strings to Kalium's and they sound great - deep and warm or bright and snarly. Came with what appeared to be DR or DA stainless strings (Xotic lists them as their own branded stainless strings).
So, now I'm up to 5 basses again - Upright, Fender Precision, Xotic Jazz, Fender/Warmoth Fretless P/J and a Breedlove ABG Fretless. With these 5 I can pretty much cover anything I'll ever play. Call me GAS over for a bit.
Oh, and here's mine. Pics were pre string change though...
John