What I have noticed from the 2-3 years that I have thrown both exclusively is there is a difference in reaction. Most of my Roto pieces remind me of the Brunswick stuff that I threw a few years back. Good continuous motion in the back with out a lot of over-reaction in the back. There are exceptions to the rule as my MCP is very strong on the back end as was is my Nomad solid.
Storm has a larger line so there are some pieces that have the same roll charachteristics as RG. To me it seems like the symmetrical balls have a smoother motion like the Dimension, Reign-of-Fire, Special Agent, Secret Agent, etc. In early results it appears the Marvel is along the lines of that as well. The pearlized Storm gear can be flippy, but 4000abralon usually cures that quickly.
I did like the low-powered RG stuff like the Mars, Venus, and Neptune. Storm didn't have anything with this low-powered of a weight block in there line. Even the Tropical Storms can still be very whippy on the back end.
"Tell me Cup, how does a great ball striker like you shoot an 82? Well I lipped out this putt on 18......"
Mike Craig - Storm Products Pro-Shop staff -Columbus, OH