have used optech straps before...from the super classic to the pro straps...
They probably worked better in terms of relieving some weight off your shoulders and necks...BUT they are bulky, and after slinging over your shoulder/neck for a while, you get hot and sweaty, esp. at the area the strap is covering, and you absorb a hell lot of sweat(the strap is not exactly breathable ..)
The bulkiness also makes it difficult to twine the strap around your wrist in those instances that you want to...
So what am i using now? Thinktank straps...these straps are really thin, but surprisingly very easy to work with..convenient to sling around on the go, easy to keep, does not make you sweat excessively, and i find it comfortable enough to use...totally love it, and ever since adopting these straps, have never had the need to look for new alternatives anymore...
yes, i believe in terms of weight bearing, the optech should be better since scientifically the larger surface area and cushioning should make it more comfortable, but its not like the ThinkTank is uncomfortable to use, it still offers comfortability that i m more than satisfied with...totally pleased...
Thinktank is not cheap though...goes for about $35 i think...but i do recommend you try...=)
The decision is up to you, we all have different preferences...
(by the way, have used the strap with D3 / 70-200 / SB-900..)