I've had both. The 60s SRT 101 is mechanical, tough, but also very long in the tooth and takes no longer available PX625 batteries. The XD11 is a late 70s model with a dead-quiet electronically controlled shutter and a LED meter display instead of the SRT's match needle readout. My only problem with the XD-11 is its 30+ year-old electronics--a sometimes failure-prone part of Minolta's last MF film cameras. I'm partial to the mechanical SRT which can still be found in quite good shape for very little $.

Lots of info here:

http://www.rokkorfiles.com/