I have no experience with a suspension based viagra product like this. Only pills so far. In theory, they should all work the same. However, factors such as your own metabolism, when you ate last and how much, how soon after eating did you take the stuff, personal expectations, etc can all have an influence. I would also be curious if there's a manufactured and "expiration" date on the product you used? I would tend to believe a suspension like this would potentially be less stable, IE: Expire sooner than a pill and lose effectiveness. What "dose" did you take? How is it dosed? Some kind of small packet? 50mg of a generic tablet works well for me. Viagra will not "turn you on", or cause desire, or a libido increase. It is only for improving blood circulation to the genitals. There's more science behind it than my simple explanation, of course.
My typical experience when I take 50mg of a pill (generic V) goes something like:
Take on an empty stomach.
Within around 30 minutes I can tell I'm slightly stuffy, or congested in my sinuses. That's when I know it's starting to get into my system.
I can get erect much more easily, however, I still have to have the desire to do so.
I get no extra staying power, or delayed ejaculation (I have heard some men report they can supposedly take longer to ejaculate). However, after I do ejaculate, I can get hard again within minutes and multiple times.
I'm not trying to be mean, but keep in mind guys you can't base how something like this 'may' work for you based on one guys' feedback. He took it once for the first time so far, and again...maybe the product he took was not even what it was supposed to be, may it was expired, maybe he just ate a big meal and/or was intoxicated, etc. A 2.5 hour or longer window before you noticed any sort of difference with your erection strength makes me suspect something was off with the product itself.
Just my feedback.