HSDPA 1.8 vs HSDPA 3.6
Both should work on HSDPA 1.8, while I got close to 1 Mbps on tests on Blackjack, I got about 400-500kbps on 8525.
Also the uplink on 8525 seemed a lot slower than the Blackjack.
Cingular's HSDPA max speed right now is 1.8Mbps, but I have not seen anyone get that speed...