I've been using Pilot Road 4/5s for the last 40K miles and I love them:
Pros:
+Super sticky in the twisties
+Heat up quickly
+VERY noticeable difference in stopping in the rain
+Tire life is good (around ~8K for the rear the way I ride)
Cons:
+Expensive
If you ride a lot in the rain and inclement weather I highly recommend these, otherwise I would go another route.
I have not tried the "GT" version yet, curious if anyone on here has.