Not much changing in the guts, but I am retiring the T5's. I'm waffling between Halides and LED's. LED's are the best, but way expensive unless I build 'em myself again.
I'm having trouble justifying the thousands compared to hundreds. Talk me into it, will ya?
Im not sure where you are getting that they are the best. I would do the halides. They only need to be run 3-4 hours a day so heat and electricity is not that bad. Plus bulbs will then last 2-3 years before needing replacement.