i have had standard oimps and i have had a teflon vcap also, the teflon out-performs the standard caps, but lets be honest this is all at a very low level, if money is no object get teflon, if it is an object be happy with standard vcaps
this is all some years back now that i owned all that jazz.
so hard to put a finer point on it all, except to say i was very happy with my teflon vcap, its performance with a supermacro 3 and an imod was tremendous
however, i have now got an order in for the hifiman to see how that can compare....you might want to think about that and also the amp3, which i own, some are claiming it to be an equal to all these expensive vcap setups, and its dirt cheap in comparison, me....i am not convinced yet and will need some more time on it to conclude.