Just getting around to scrolling through Bryan's preview, another big difference with the R1 is a much deeper buffer than the R3. The R3 can shoot full RAW at 30 fps for 5 seconds (150 frames), the R1 can seemingly just keep going (1000+ frames). The 1/400 s flash sync is also much improved over the R3 (Bryan has an incorrect value of 1/320 s for the ES sync).