I have given up the hobby in the interest of putting my marriage back together.  But from a few years of philandering post cardiac surgery and ongoing cardiac meds I have some experience with the phenomenon.

ED pills worked OK for awhile but when they started to become less reliable and producing only half-staff erections I finally went to a urologist.  He prescribed the injectable stuff, prostaglandin in my case, and that is much more reliable.  It works in 15 minutes or less and produces a nice hard erection. It is also A LOT less expensive.  The trick is learning the appropriate dose and losing any squeamishness about sticking a needle (small though it is, an insulin needle) into the side of your dick.   A few times I used too much and ended up with a 3 hour, uncomfortable erection.  Then I cut back and it didn't work at all.  I think I have it right now, though. 1-2 hours is a happy result, since that span allows for extensive foreplay and DATY followed by lengthy intercourse.

It does delay ejaculation, which can be a positive.  However, on second rounds I almost never come again.  This is fine with me and was OK with my partners as long as they understood what was happening and didn't become disappointed they couldn't bring me off again.  The other drawback is that the directions say don't repeat injections within a 24 hour period, so sex at night might preclude sex in the morning.  I have done half doses the next morning and sometimes that works, but might be risky.

Another negative side effect is the aching penis post-coitus.  This lasts an hour or two even after the erection subsides.  

Another positive is that ED pills began to work again.  So I can alternate them.  The pills don't retard ejacution as much and the side effects are different  -- i.e. mild headache manageable with Tylenol instead of aching dick.