I've got 2 other guitars that I've tried/compared to the 151s: a
Jackson Kelly-style with a Duncan in the bridge, and an Ibanez GRX70 which is a really cheap guitar with some kind of cheap humbuckers along with it. The GRX70 doesn't sound so good -- it's a bit brighter, but the Kelly with the Duncan just screams. Both of those guitars compared to the Jem5 with the 151s are more bright-sounding. Maybe there's something wrong with the Jem5, (it isn't in such great health) but I may have the pickup placement set wrong. I bought the Jem5 from someone and he took out the Evolutions (I think it came with them) and put in the 151s, so maybe they're just really old and are having trouble getting a brighter tone. I'm really not sure what the problem is though.
I've already taken the pups out of it and man am I ever having a time getting them back in; I can't get the little springs to go into place when I put the long screws back into the pick guard to adjust the pup height, but maybe I'm supposed to take the pick guard off when I'm doing that, heh.
I'll have to fool with the pup height and see if that maybe cures the problem, but one thing is for sure that I've noticed about the 151s: the note-separation is amazingly accurate. This may have something to do with them being so weak though...