Do the sprocket-type tensioners provide any better performance?
I actually am still using the stock tensioner. I found that if the rear sprocket is perfectly tightened and if the tensioner is perfectly aligned with the engine sprocket, it won't move at all! So I've left it that way for months now. The only maintenence I've done was adding grease to the wheel so that the chain glides over it better.
I do plan on adding a chain to the original tensioner like here:
That way I can keep the tensioner and still give it something to prevent it from slipping into the spokes, just in case!