Good point, Sean... we'll ask Sanjay... someone write all this junk down.
FWIW, T5s win many aquarist's hearts through multiple things... Number one, they have enough light for any coral that does well under MH, although the coral may look slightly different than under MH. Also, they run cool and very efficient. I love having more than enough light for my tank at only 156w. Also, with less wattage above my tank, there is also less heat going into it. I don't have to run a chiller, which gets into quite a bit of money with electricity. T5s also last longer than MH or PCs. You only have to replace the bulbs every 12 to 18 months. Thats not bad at all! At minimum twice that of PCs and MH.
In my opinion, T5s are worth the extra cost over PCs and pay for themselves fairly quickly. I've never had PCs, but from what I understand, some SPS may not do too well with them.
And, as has already been mentioned, watts-per-gallon doesn't really matter. Its all about the depth. Which brings up another point, T5s compete with MH only if they have individual reflectors. IceCap reflectors are where its at for 12.5" tanks, simply because 4 Tek reflectors won't fit and 4 IceCap reflectors will.
Hope this helps some. Your PCs are by no means inadequate and may serve you perfectly fine for what you want to do. If they do, cool beans. :thumbsup: If you decide later down the road you're not happy with them, you can always come over to the dark side... I mean T5s.
Brandon