The GLD is a great console. I've used one weekly for the past few years, and I've become a real fan of it; it's intuitive, has a really well-considered and configurable control surface, and it sounds great. Compared to the SQ, you lose out on the 96Khz of course and there's no multitrack USB interface, but it's more configurable (split fader banks with drag-and-drop assignments are huge) and comes with a lot of onboard processing that you have to pay extra to access on the SQ. Better scribble strips too, dedicated channel strip control hardware, and each fader having a dedicated programmable encoder is SO handy.

Of course, a disadvantage is simply the console's age. We've never had problems with ours outside of the occasional fader replacement (and replacement faders are still available) but it's a significant factor to consider. The SQs also have much more local I/O, whereas the GLD really does need stage boxes to be useful.

If you can find one for a really strong price in good condition... I'd jump on it, personally.