I love my T5's although they can get quite costly to replace. I have a total of 24 bulbs over my 350 (2 four foot fixtures, 8 and 10 bulbs each) and 1 three foot 6 bulb fixture on the side of the 6 foot tank. Also have T5's over both of my frag tanks (4 foot 6 bulb fixtures each). They're all ATI fixtures (2 new the rest bought used) and a pain to remove to change bulbs or get better access to the tank but I love the spread, the versatility and the colour/growth I get. I use mostly blue plus, but each fixture has at least 1 coral plus and 1 purple plus, with the frag tanks having 2 coral plus for better growth. I also have supplemental LED lighting over my display in the form of 1 four foot reefbrite and 2 of those lights Shawn sells. I have only LEDs over my inline anemone tank and mantis tank though, mostly blue but a 50/50 on for 6 hours over my nem tank (avatar pic).
Maybe the subject of another post, but I tried extending the like of my bulbs after watching the BRS test that said the drop off on blue plus for example was minimal after 8-10 months, but replaced them once I started getting cyano in places I hadn't before. I also had colour loss on some of my sps. As I feed a lot and typically carry more than recommended phosphates and nitrates, from the reading I've done I know I need stronger lighting,