I played an RBX 374 as my main bass for almost 2 years. Not the 5-string version, but very similar.
I've tried out the 375 a few times, and I've NEVER liked the way those pickups sound for notes under D or so -- but I haven't played one in ages, so your millage may vary.
My RBX 374 had one of the nicest necks I've ever played on. It wasn't completely rattle free, but I wasn't that good at playing/setting up when I used it. The bass isn't light, but it isn't heavy either; I thought it had a great weight/balance.
The sound of the bass is somewhat "dark" sounding. I don't think it sounds great with both pickups blended together, but you can get some great tones if you edge the balance slightly forward or back. It's VERY versatile and very easy to switch from tone to tone. I always had to EQ the sound somewhat when I used it (boost the low mids quite a bit usually), whereas with my MM Bongo I can often just plug and play.
The preamp isn't great, no. Boosting highs makes it hissy and doesn't do that much for the sound (slight boosts sounds fine), and boosting bass makes it very muddy. However, the preamp works GREAT for cutting (eg, cutting highs, etc). A quick turn of the treble knob can turn you from a bright sound to a deep sound very quickly.
And, my most favourite thing about this bass apart from the neck was... the neck pickup. I just LOVED the sound of that pickup soloed. Kind of like a P-bass but much grittier and darker.
I also had flats on mine for a while, and it sounded VERY interesting. Wish I'd kept the bass, but I was just bored with it and really wanted to just get rid of it and try something new.
The finish on mine was also quite weak. It looked lovely, but flaked off very easily!
Anyway, to sum up, it's a bit dark sounding (not too much warmth), has a GREAT neck, and suits gritty rock/metal very well.
For the price, VERY VERY worth checking out. And if you order one without trying it, I doubt you'd be too disapointed -- very versatile bass, and you can always pop EMGs in if you don't like the pickups or whatever (some EMGs will pop right in).
My Musicman Bongo is better than my 374 in every way... but I still miss it kinda...
Hope this helped
