It depends on where you plan on buying it from, if playing ebay roulette I would buy the SRT because its less likely to have hidden problems. All you need to know about the SRT is if the meter works.
If you are set on an XD-11 buy one from KEH.
I've either owned or used at least one of every series that was in the Minolta line up.
The XD -11 is the one I pick up first.