Definitely T5 - just find something in your price range and hopefully have better luck that what you got before. Sometimes more $$$ is worth it, sometimes not.
I don't think Sunblasters are rated for use over uncovered tanks.
I run Aquatic Life T5s (check out the hybrid unit, it will hold your XR15s too) but if I could do it all again I would go full on Sunpower with a ReefBrite add on.