Avalanche hands down. I can't say much for the others because the Avalanche pretty much has my area dominated when it comes to urethane. Even friends of mine that normally shy away from Brunswick have this ball and love it. As for mine, it works wonders playing on most sport patterns under 39' and even playing up the oil line on THS. I've had it at surfaces from highly polished to 1000 and it's amazing at any surface. Basically now it's kept from 1000-2000 grit to be for playing the twig on short sport shots

My Avalanche is a "carry" machine.  I can use it much more than I thought I would at first.

 

 

I have seen the natural, natural pearl, grenade, and vbp ogre urethane in action....

 

the vbp looks the best and seems to carry the best of the 4 ive seen....it really did its job for the older guy using it he has too much hand and not enought speed and limberness to get it down the lane...so he throws all low end everything plus alot of plastic even, and looked impressive as well..

 

IMO the grenade is my second favorite....i actually got to throw that one...pretty good too...

 

dont forget there is an older amf hype that is urethane as well...and the seismic desperado as well...many have said good things about that ball too..

 

They don't keep me around because I'm beautiful.
So which urethane ball did you recommend?