My SuperNova is a really nice ball for that shape of arc. It's too much for a down and in ball though unless I'm on synthetics. It rolls out early on the guardian even when polished unless I keep it inside (sometimes forcing me to deal with over/under in the process).

I just picked up the SuperNova XP hoping it would allow me to play down and in on either lane surface since it goes longer and still has good back end. Haven't punched it out yet though.

If you have Bowling This Month, look at their ball graph. It will give you a good idea where all the newest equipment stands regarding length and back end. If you don't, see if someone you know does (or maybe they put it online).
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There is nothing so easy to learn as experience and nothing so hard to apply.