The SMG II is not an abrupt transmission (on the M3). Nor is the SMG III in the M5/M6. I owned an 05 M3 and I loved the SMG so much I ordered an 06. The M3 and all the M cars with SMG have drivelogic which gives you 11 different programs for the transmission. The shifts can be programmed for ideal city and aggressive driving (hence the M badge). So, no jerkiness or "abrupt" shifts if you know how what you're doing. You drive the SMG like an SMG, not a manual.
The SMG however on non-M BMWs does not have the drivelogic and you have only one program for the sequential and auto mode. That transmission is jerky. It will still be easier her for to drive