Each of the three -- Viagra, Cialis, and Levitra -- provides a different effect on me. So, I select depending on what I want sexually.
Viagra -- the first for most of us, usually leaves me with a slight head ache. This is usually solved with an advil, but I had rather not have to take pain medication. One 100 mg Viagra taken on an empty stomach produces erections after an hour or so. There is no problem with waiting several hours until the occasion arises, the functional hardon being produced. The morning after having taken one, I awake with a bone, although I have climaxed the night before. This is not always the case, and I'm prone to harden during that day, as well, with that Viagra.
Cialis -- my favorite. One (I'm not sure the mg) and for the next two or three days my erections are the firm, eagerly demanding type that give me great pleasure in performance and satisfaction. With Cialis I often awaken through the nights hard as well as the daily ones begging for action.
Levitra -- as with the other two, taken on an empty stomach, a 20mg has failed to produce the rigid dick from Viagra and Cialis. Perhaps I didn't have the situations after taking Levitra that I had with the other ones and I will try Levitra again, for a double check. A slight headache also resulted from Levitra.
I'll add that without any pills, my hardons are sufficent for masturbating and climaxing anytime, 24/7. It's the standing up and throbbing hardons that I make reference to in the above.
Hopefully, this information will be beneficial to some of you.