I'm not sure why L-1500/1505s get the tepid reaction they do. Resale prices are among the lowest of all current G&L models and they seem to take forever to sell. But I'll tell you this--run one in passive/parallel into a SVT-type rig and you have an incredible blend of cut, punch, and balls. My 1505 would be my #1 if it wasn't for how comfortable and easy my L-5000 plays.
I don't get it either. The reason it never quite worked in the mix for me before is because I have a rig with really tight lows that made the L-1000 sit perfectly with the guitar. Now that the guitar is gone, I can boost the lows on my amp just a touch with an HPF and the L-1500 is killer. It blows away any Stingray that I've played because it keeps the highs a bit smoother. It also pairs really nicely with the EQ points on my GK MB Fusion 500.