Ah, the great T5 and MH debate
I'd say that if the ATI SunPower is in your price range, full steam ahead. You might lose the shimmer effect, but the pure customization, lack of heat, and colour that can be reproduced in a T5 setup is what puts it ahead of MH. ATI's are probably the best products on the T5 market and you're going to see little, if any, difference between them and MH.
My two cents.