I have worn mine for two days running and I don't have the aches and pains I usually get from wearing my camera in the variety of other positions I mentioned in my previous post. It took a little bit of getting used to on the first day (having £1, 500 worth of camera equipment dangling upside down near my butt is kind of weird!) but once I got into the swing of things it was a revelation. Just being able to glide the camera up for a shot and then release it back to its "resting position" without having to fumble with straps was worth the purchase price alone. I did find that my larger lens (the 85mm) tended to swing around quite a bit but I think this may be to do with how I have the fastener locked rather than how the R-strap is designed... I probably just need to play with it a bit more.
The neck strap doesn't cut into my neck or shoulder even with my lady bumps and lumps :) :) and I like that the camera is nestled discretely by my side (I don't scream "person with camera approaching" anymore). For the studio photographer, who can regularly put their camera down without fear of it being 'permanently borrowed' by a passing stranger, I can't see any real benefit in buying the R-strap. Or for the photographer with a willing assistant to hold and carry things, it probably isn't a must-have. But for anyone else who is tired of paying out for expensive physiotherapy sessions (or sick of trying to coax a partner into giving them an après-shoot massage) and wants a hands-free camera carrying system: the R-strap is for you.
p.s. if the R-strap peeps read this, I wouldn't say no to another one please!
Also, if anyone is wondering, HM Revenue & Customs did catch up with me and I have to pay £12.80 in duty.