As you can see by all the responses: "This is almost an unanswerable question." The balls are very similar. So similar that Storm is discontinuing the Fire Line this year. I have a Hy-Road and a Surefire(inverted Rapid Fire core). Both balls have hybrid coverstocks. Sometime I like one better, sometimes the other. Note, the pros who have the same choice you are asking about almost always choose the "Troad". To separate the reactions of the two Storm balls I own, I keep the Surefire polished and the Hy-Road at 2000 Abralon. If I were you I would wait and see what the Reign offers if you really want another Storm medium oil ball. Or, you could get a Roto Grip Nomad solid which has what amounts to a more dynamic version of the Thunder Core - the Rotary Core - this would give you more backend than your T-Road.

I experience the opposite of cobalt bomb.  My Rapid Fire Pearl is snappier.  After a few surface changes with my Hyroad and my RFP I actually had them reading the lane the exact same (not by design), but that goes to what dough was talking about on why storm discontinued the Fire Line.

IMHO it wouldn't be worth owning both a T-Road Pearl and a Rapid Fire Pearl unless you want to change the surfaces to get different reactions.  My RFP is one of the most skid flip balls I have owned.  It is drilled pin up with a 3" pin.

I am surprised so many people had these balls the same. I had one T-Road Solid and three Rapid Fire Solids. The T-Road for me was very smooth on the back. The three different Rapid Fire Solids I had all hooked a lot in the back. The T-Road solid was about 7 stronger than the strongest Rapid Fire that I had with the same surface. I was very disappointed that the Rapid Fire was discontinued as it was one of my favorites over the last year and a half.