I was running on this for about a year, and it was my best excperience with lighting so fare. Here in norway you can only get T8 end T5 in the colors we need for aquariums, so no CF or anything like that. There are tons of plantgeeks who use T5 now, and more joining every day.
T5 does provide better lumen/watt output than T8. Produces say as much as 150% better, but that I really doubth. But since the tubes are so thin, you can fitt more than you will ever need over you tank. I have a bow-front tank, but this meant that only a small part og the tank could fit the whole length of the tube. So, I installed six 54W tubes over my tank, two daylight, two grolux and two full-spectrums. And boy did this work out great! Tank was pearling like crazy, and I got red color on my plants like I have never seen before. Only problem was that the T5 tubes run much hoter than T8, and so my water temperatur rised to 32degress. But I just installed a couple of fans, and the problem was fixed. During this year I never once had problems with alge or a singel species of plants.
But some months ago I decided to try out a open tank, and so I went with MH pendels hanging for the roof. This is not working to well, my red plants are looking pale, and for the first time since I startet a real plantet tank I have some slight problem with green alge on my plants. Guess this is manly due to the very limitied color range on MH...
But my advice is, try it out, it's absolutely great!
