I thought they were all the same until Scott Koplin sent me the new travel plate and lightweight sta. I dived those bits in Mexico in January with single tanks and thought "Nice, works the same and I don't have the weight to carry on the plane." But then I mounted doubles on the cut-down lightweight plate to do some cave-diving and realized how much more easily I could reach all the manifold knobs for shutdown drills.
I emailed Scott when I got home and asked why that would be. He replied that he had been doing some research with divers on the left coast and discovered that the angles on the upper slots normally used could be changed, and the result was a better ride position of the plate and tank. I matched my old plate to the new travel plate and sho' nuff, the slots are slightly different. But what a difference in the way the rig rides on my back.
Hope I'm not giving away any trade secrets here, but if any of you get a chance, ya gotta beg, borrow or steal one of the newly configed Koplin plates. It's pretty nice.
Scott's very approachable about this stuff, and he really seems to know his stuff when it comes to the nuances of dive gear design. I'm now impatiently awaiting the intro of the new wings from Oxycheq, the distributor of Scott's gear. If the wings are as good as the plates and STA's, I'm already sold. 8)
JohnF