I have played a lot of basses, but I am not sure exactly how to compare my Carvin b50 (You can see pix on the b40/b50 thread)..
Maybe I would compare it to the well made import basses (sadowsky, lakland, etc) and to some american mades like MM and G and L...definitely to the higher end japanese (Yamaha pattitucci, Ibanez prestige, etc) and of course it compares to all fenders except the custom shop...but I am thinking specifically of Victor Bailey, Marcus Miller...those kinds.
As much as I love my Carvin (It is my main electric now) I don't think I would compare it to the Lulls, celinders, USA laklands or USA sadowskys. Its a great bass but not mind blowingly great like those.
But where it really excels is the fact that it is really "customizable" in that you pick the color and everything else. Few companies except boutiques will do that, right?
Usually I have to settle for whatever a company has...but not with the Carvin. I wanted green quilt, I got green quilt!
Oh, and it is true that in the past, Carvin electronics and pups were kind of boring. Not any more. The new pups on all their models are great! You might actually see them finally being used to mod other basses.
The B40/B50 and SN series have one other majorly cool thing going for them...a passive tone knob that can be used at the same time as the active electronics! On so many basses, it's either one or the other...and usually going into the passive mode (like when your batt dies mid-gig) you don't have any tone control....not so with the Carvin! On many active electronics, as concerns the high end you are face with only one option: Less treble and more treble, but there is no way to cut it down completely like with a passive tone....with my Carvin I can do both, and that is a huge plus for me (and for anyone that also wants to use an electric to play roots music)