I've only used the compact florescent lighting from AH Supply, but I'm really pretty happy with it. I've had it for about two years in two tanks and not even a blown bulb yet. The light is still pretty bright, but it has dimmed some.
The cost of the T5's scares me a little bit. The heat from them is a little scary too. Maybe I'm a little worried, but I'd be careful what was around the lighting. We used a T5 light for an experiement in a lab, and only after being on for less than a minute it was incredibly hot. I've never had one so maybe I'm over cautious. Its just the fact that I won't be home if something does go wrong.