I have a 12gl and like it for its size. If I was looking at the 24, I would be very tempted to look at the new Red Sea cube. It comes with all the mods I ended up putting on my JBJ 12. It's more expensive, of course but if I had to go back and do it again I'd have purchased the red sea.
My JBJ12 is a good unit, it came with bio balls that I yanked out, upgraded the pump to a MJ 900, changed the lighting out with a kit from
www.nanotuners.com , added an ICA chilling unit and run a reefkeeper II on it to manage the lights, heater and chiller.
HTH