Hi Mark,
No real issues with the SDM. The secondary mirror came loose recently when setting up at the Pony Club - probably more so because of the drive/bouncing around at the back of the ute. Apart from that, pretty much everything falls in place when setting up the first time around.
I'll be at SPSP with the scope, so if your there, more than welcome to give my scope a workout
!
Cheers, Norm