Originally Posted by
Hermanni
I'd say any hero is a good pick (barring Techies), but Viper isn't all that general. His niche is pinning down single enemies and outlasting enemies (or at least in the most common playstyle), but he certainly is devastating in almost any pub game.
Thing about Viper is that he punishes bad judgement. Like you said, in average level pub games he can easily take a kill on a badly positioned enemy, and he will punish anyone who attempts to take offensive against him and fails. It's very common for inexperienced or even experienced players to under-estimate Viper and end up dying because they thought they could kill him before he killed them or because they thought they could get away if he took the initiative.