I posted in WV CHEVY MANN's thread my thoughts, which I'll rehash here....
I personally like the release lever. The way it is supposed to function is to relieve the belt tension when door is closed. This allows you to leave a little slack in the belt for comfort. When door is opened, tension is applied to the retracrtor assembly, which allows the belt to return to the retractor assembly in the inner panel of the quarter (or B pillar on sedans/wagons). One of the things GM got "right", IMO.
For drag racing, you want belts that are tight to keep you in place in tht event of a mishap. For regular driving, not so much. I don't advocate having feet of slack in the shoulder harness, just enough to relieve the constant pull against you. Bugs the daylights out of me every time I drive a "new" car.
To my knowledge nobody manufactures a true OE style replacement, using the release levers. And why would they? Small market, and half the existing owners want to replace them rather than repair the system. Add to that the huge liability exposure of manufacturing a safety-related item, and it doesn't make sense for most aftermarket manufacturers.
The OE assembly, with fresh webbing, should work as intended. Most people never really consider their belts, but if you compare your original belts to the belts in a new car, you'll see just how stiff/frayed/dirty they get. This in turn causes problems with the force required to allow the belt to be drawn back into the assembly.