I have tried V and C. The V works well. It allowed me to get back up for a second round very easily. The side effects include a few moments of flush face and mild stuffy nose. It does make it much more dificult for me to pop, and for that reason it was not good when I was doing load dumps. Try small doses of V to start, like 25mg. The longer you take it, the larger dose you will need.
The Cialis gave me medium results. It did make it easier to get it up again right after a pop, but the wood was not as solid as with the V. A viagra boner is so solid you could hang your jacket off your junk. The Cialis gave me its classic side effect, though. About 2 days later, I got a killer back ache that lasted for about 2 days. I threw the rest away after that.
I have not tried Levitra, but I know guys who like it.