I don't generally trust websites that sell viagra, but I would trust MarleyDrug.com for the fact that apart from having a cool, professional and legit looking website, they have a television advertisement where the owner himself is the host, they have been registered online for over 12 years (the website was created in 2007), they have a physical address that looks totally legitimate, they don't have a single negative review on Google Maps.
I couldn't find a single person on the internet that referred to them as a scam and believe me, I tried hard on it.