I guess I'll throw a detailed review up on here since I said I would after a few months of playing. I've been gigging for 6 months with it now. Keep in mind my comparisons come from playing a Shen SB80 for 6 years, and I play 100% pizz.
The bass is very comfortable to play. Much more so than my old one. I could do comparisons on bouts and weight and such to figure out why I suppose, but I'd rather just play it. Physically it still feels good playing after three hours. This is important to me as I have back and neck problems that aren't going anywhere. Not once have I felt like I was fighting it in any way.
The neck took me a little bit to get used to. I would say that it's medium-thick if that makes sense. The Shen had a Louisville slugger for a neck, which I liked because I have large hands (I'm 6'-5"). When I tried Kays, it took about 30 seconds for me to say no because of the tiny necks. After a few months of playing I adjusted accordingly, and have no issues playing on the "smaller" neck. It's probably a perfect size for the average person.
It was setup decent from the shop, though I've played with the setup since I've gotten it. Decent probably isn't a fair term. It was professionally setup per our discussions with the strings I'd requested, bridge fitted perfect, and ready to gig. This isn't a criticism of Upton. I think any new bass is going to get messed around with a bit before a player finds his sweet spot. It's easy to play, and has made me "better" instantly. I say that because there were things I would play on my old bass that felt like gymnastics, and now feel like bass playing. I'm able to more clearly articulate what's going on in my head to my hands now without a fight.
I changed the strings and raised the string height some, but I'm still not convinced it's where I want it. I was also in Mystic for less than 24 hours, so it wasn't as if we had time to play with it and make adjustments at the shop (which those guys will take care of). It's first summer is coming, so I'll see what's what now. We have very humid summers up here.
The bass sounds great for a ply, and for the type of sound/music I play. One would assume that it will develop more character the more it is played. I put my used set of Lenzner guts on it, which are raw except for the E. Volume is uniform across all four strings. This was a big problem for me on my old bass. I can access higher positions now with clarity (limitations where appropriate with gut), which was something else I had to avoid with my old bass. My Shen was louder acoustically, but louder doesn't equate to better tone. The Upton kills it in that department. It's also a baby, so it has plenty of time to open up.
It's also worth noting that when I amplify, it is much more even than what I had dealt with before. My pickup (Rev Solo) is wing mounted on the bass side, but I have no problem EQ-ing clarity for each string. On my old bass it was feast or famine with respect to bass/treble mounting. This could be a separate discussion though. My point is that it amplifies nicely with their pickup, and isn't as fussy as many of my other piezo experiences (like most I've tried every one on the market).
Tuners are great - smooth and stay put. Not much to report here.
Looks....Upton owns in this department from the entry level ply all the way up. Just look at pictures in the Upton Bass Club thread. Their basses all look awesome. A couple of knowledgeable people have assumed I spent a couple thousand more than I did just based on the aesthetics of the bass. That's all that needs to be said. Beautiful instruments, period.
For me it was a huge step up, and a big investment. I'm happy I did it. The Upton Standard may be considered an entry level bass, but it's Upton's entry level - which IMO is a major cut above what many other manufacturers would call their entry level.