I've done two... (going to be 3 in June). Once with the UK school, and once with the German one.
I never found it to be particularly hard work, and I"m carrying 10 to 16 kilos of extra weight.. I do walk with the dog for over half an hour every night.. (realy walk, not standing around watching the dog sniff)
I did the 1200 GS for the UK school, and took it easy and never dropped it after the 'learning to pick it up session'.
As I own a GSA now, I did the GSA for the german school, which felt easier to me than the UK school. I found it very easy going on the GSA. No drops except in the first 5 minutes and in the sand-pit, which was expected.
In my opinion, if you ride a push-bike, very slowly, mounting curbs and stuff (mountain biking technical).. you fill find riding in the ORS easier... (and I agree about the 1200's power delivery making it easier to ride in the school.)
Al...