I like T5's.
I have had the others, still have a PC + HQI mix.
It use less energy to achieve the same thing with T5's.
Over time, this cost less, and the price is similar to MH's for T5's.
The key is really having good spread that is even for plants, corals etc, you have to raise the MH's up higher(thus lose intensity), but gain a more even spread. With T5's, you have a long linear source, with MH's just a single point source.
With T5's, you have multiple bulbs and switches for each, so you adjust the lighting very easily and use timers. This allows you to use less light when you are away, and more if you want to garden more later. If you have several tanks and larger tanks, T5's are pretty cheap on the electric bill.
I have and use them on deeper tanks, 24" for all, I use mostly PC's and T5's, even though I have MH HQI's. I simply do not need them and they cause me more work, time, and energy cost.
Regards,
Tom Barr