If I take it on an empty stomach, 15 min before I arrive, it seems to be ready when I am.

There is a study that ED drugs do delay climax.  The study was done with men with PE.  
Due to a partial spinal cord injury, I need to use a bit of V.  I use the minimum effective dose.
I find more problem with condoms & getting the sensation in the right place...  With some partners I can come pretty quickly...  others, can't find the right spot with a treasure map & GPS.  
j

I'm in my mid forties and was introduced to Viagra about 10 years ago from a friend who was a serious poon hound; I've use it recreationally ever since and currently have a prescription from my physician.

For me, Viagra gives me one less thing to worry about!

To your question, I think it may give me more duration but if nothing else, it absolutely gives me more control. I don't "need" to take Viagra for medical reasons, as in my civilian life with the significant other it's not an issue. I choose to use "Vitamin V" when going into a new encounter with a new lady, I always get nervous and worry about performing adequately but 25 milligrams of the magic powder and I've never had a problem.

Truth be told... ain't nothin worse than limp dickin it with a hottie you finally closed or taking off the panties... been there, done that, not cool at all... and never again my friend!

I'd like to shake the hand of the great inventor of "Vitamin V"... next to the internet, it's the greatest invention of my time!!!

Yes, I do sometimes have this problem, though not always.  I don't mind it too much if it takes a long time but sometimes I can't climax at all which is a bummer.

i think i'm gonna reduce my dose and see how that goes.

Viagra is especially notorious for causing this problem at higher doses.  The therapeutic dose of viagra is usually 25-50 mg but most get 100 mg pills to save $$$.  Unfortunately many people taking ED meds have no idea of the best way or dosage to take because they have not been prescribed.  So they take the entire pill, 100 mg, essentially dosing themselves.  Even if you cut the pills in half your are starting at a very high dosage, 50 mg.  Some are extremely sensitive compared to others on the same medication. You may need to try a different ED med all together or your dosage may need to be adjusted.   It's not just you, this is very common,  sounds like your meds were prescribed, talk to your doctor and tell them your problem so you can have your dosage changed or try a different medication.
Doc