I realize  that Cialis lasts  up to  36 hours, Viagra about 2 to 4,   I am not certain about Levitra.
I have tried  Viagra, and   I find not much difference between my normal  erections,and supposedly "enhanced "erections, except that  the major "enhancements" are a headache (Aspirin helps) , And a  stufffy nose. I recently was given  a free medical sample of Cialis, and tried it, It seemed to work better than Viagra.(Even woke up with my  old teenagestyle "Stiffy!). Still got the  Headache  and stuffy nose, but only for an hour or so. Have yet to try Cialis. ......Any new, or  old  views on   effectiveness side effects, stiffy factor etc, would be appreciated no matter  whether    used as recreational, or as a necessity.

What a great name for a provider!  If erection lasts over four hours see ATM!  It could be expensive!

I agree.  I wanna "See Alice"; she has big tits.

Hear "see alice" gives lots of headaches and is not as turned on as the big "v" is. this has been on the boards before - check back in time...

White Rabbit!

My SO is in primary healthcare and sees a lot of patients on this (many of whom she refers to urologists.)  However, I've tried all three and can make the following feedback, along with some of her comments:

Viagra: Tried and true.  Minimal side-effects on the broadest population.  Not a long half-life (4 hours seems to be max) and not so good for second and subsequent erections.  Used to be the urologist's favorite but has been replaced by Cialis for many.  Still considered the safest of the three, and certainly has the longest and widest field experience to back up the clinical trials.

Levitra: Somewhat stronger than Viagra, providing significant improvement to some men that don't get a lot of help from Viagra.  Generally has the same shortcomings (pardon the pun) as Viagra in terms of half-life and recovery, and with potentially more side-effects and more contra-indications.

Cialis: Generally, the new urologist's fav.  Long-lasting (36 hours is an average; I regularly get 48 hours of affect from one tab), effective, and with good recovery.  However, it has more side-effects than Viagra (see someone else's comments here about backache; I don't experience it, but a small but significant percentage of men do.)  More and more urologists are moving to a standard regimen of Tuesday/Thursday/Saturday dosing of this drug with very good success.

In a nutshell: Cialis is best for me.  Your milage may vary.