There are two things to consider. Firstly what do you consider “best”, and secondly how does your body react to the pill- and to the other anti-ED treatments on the market?
If you consider “best” to be the hardest penile erections, then because all oral treatments work on your body in similar ways, it’s unlikely that you would see a difference between Viagra and Cialis and Levitra- the three main drugs for ED. That said, some men swear that Viagra gives you more body to your erection.
If you consider “best” to be a drug that lasts for a day or more, then Viagra is not the one for you. It has a window of activity for 1-5 hours, then tails away quite quickly. You are unlikely to be able to enjoy the effects of one pill for more than one or two sexual bouts of activity. For most people that is not a deal-breaker.
Finally, if you consider “best” to be the anti-ED drug that gives you less side effects, then you need to move on to the second thing to consider- how your body reacts to the drug. We are all individuals and although the drug is likely to “work” for 80% of men, the side effects it may produce vary from none whatsoever, to those that actually prevent enjoyment of the sexual act- defeating the purpose of taking the pill in the first place!
You should have discussed your ED with your GP first because he or she will want to make sure it is safe for you. Some combinations of medications and/or medical conditions make this and other ED treatments unsuitable, and even dangerous. But assuming it has been prescribed for you, it is then for you to take the pill, and see what side effects, if any, occur, and if they do occur, if they are sufficiently debilitating to make you want to stop taking the pill.
Some men experience no side effects whatsoever while most other experience relatively minor side effects, such as some nasal congestion, a flushed face, headaches, some visual changes (commonly a blue tint) or an upset stomach. These will be well known to you doctor and these can be discussed with him or her to see if you should try another drug, or perhaps lessen the dose.Viagra has certainly earned a reputation for being the first and the foremost oral treatment for ED. It has been extensively tested and been in use for getting on for over 15 years now. It should arguably be the top of your list when considering an oral ED treatment. But discuss it with your doctor first!