T5's are better lights for a few reasons.
1 - When coupled with individual reflectors, close to 100% of the light produced is directed into the tank. With PC's half the light goes up and is reflected directly back into the bulb.
2 - For the wattage, the T5's produce more par for energy used than PC's.
3 - Color combinations in T5's are more advanced than PC's. There are more avaliable for specific marine applications.
In the end when you look at the asthetics of T5's as well as how much more energy they transfer to the tank, there's really no comparison. There are quite a few folks (incl me) that are successfully growing demanding corals (SPS) under T5's. I dont think there is anyone attempting that under PC's alone.
The real answer to your question is in what you intend on keeping in your tank. LPS corals and mushrooms would do ok under PC's. Corals with higher light demands take T5's or Mh lighting.