I don't use the Hasselblad quick release, it is a nice idea but it is not possible to do portrait with it. The RRS L-Plate fits over the body like a glove. Only other downside I found (besides the sync cable thingy) is that the centermarkings are very hard to see, they should go over the side of the plate, not just on top of it.
Take a RRS plate and a RRS quickrelease clamp and you have what you want. A system where you can easily and quickly attach & detach your body either in portrait or landscape. You don't even have to undo the clamp entirely, you can slide it in if you only loosen it somewhat.
When you ever consider doing panoramas with your H, don't get the regular RRS clamp but go for the PCL1 pano clamp immediately. That is a clamp and a panohead in one package. You can leave the L-bracket on the H which is what I do. I find it is not in the way of working handheld.
Something that doesn't show on images is the build quality of the RRS clamps and brackets. It is very well built, very rugged. I have had manfrotto QR plates, novoflex plates/heads (pano), Minolta panohead, Nikon panoheads, etc.. none of them had that ruggedness while still keeping silky smooth operation.
I saw someone mention he had movement in his clamp and bracket, that must have been another brand of clamp if not he should return the thing to RRS to get it replaced.
