I have had a couple balls with strong covers and they didnt really work for me, the only one that did was a Virtual Gravity which I liked alot. I had a Mutant Cell and a CSystem 3.5 and I didnt care for either. He did mention that if I was changing my arsenal I should look at the Nano to go above the Eagle. I know this kills him since he is a Track Staff member.
I will say I really like both 505T and 715T, when I had them drilled I wasnt bowling a lot of tourneys, now i am and the 715T drilled that way does ok in heavier oil, but Id like to see it turn a bit harder. The 505T is a great med/heavy and fresh THS ball. Very consistent roll and reads the lane great. I didnt care for the "A" balls and that why I ventured to 900 Global. The Bank pearl although not skid/flip it is still angular for me. It has become my first ball out on THS.
My Current Arsenal:
715T................... 65x4.4x30 1000AB
505T................... 65x4.5x30 2000AB
Bank Pearl...........60x5x40 1500 polished
Dark Star.............70x3.5x40 1500 polished
Red Backlash.......75x3x35 2000 polished