I've been using 900 since they started, and wouldn't go anywhere else. Covers get super clean through the fronts, and their ball designer (Nick, take a bow.) is top notch. The src core rolls great, and is being used in the bank, bank pearl, bank roll, and green Mamba. Coverstock strength is easy to determine where it fits in your arsenal. I'm one of three people using 900/AMF in my league, and my ball reaction looks killer. I'm actually going to pick up a bank roll, Pearl and Mamba just because the weightblock rolls so well. For me. YMMV.