It's true they are really not well-known. Great basses though. I had an L2000 fretless for a few years but it was sadly destroyed in a house fire. Wonderful instrument.
My ASAT bass is basically the same thing in a different shape (oh and with frets). Again, superb. When I bought that about a year ago, I went into the bass shop without an upper limit on what I was willing to spend. The G&L beat rivals costing 2 or 3 times the price (some of which was down to lack of available sounds, but often it was just inferior workmanship and playability).
I tried a Tribute also that day, and was absolutely astounded at how good that was for the money.
I have an ASAT Classic S guitar also. Now that thing is an absolute joy. I know two guitarists who currently are looking to source a G&L on the strength of playing that (one of them wasn't even plugged in).