Long answer
It depends. Sometimes I feel attracted to a game only because I've seen some screenshot (happened with "Caligula Effect" on Vita and "Gungnir" on PSP): I immediately decided to buy them, I did, I didn't regret it. Sometimes I carefully read many reviews and watch many gameplay/longplay videos without caring for spoilers, sometimes I'm okay with the comments and I think "okay I'll pass on this one", sometimes I still like what I see and I decide to play it anyway. Sometimes (like with "Assassin's Creed Chronicles Russia") I felt quite attracted by the gameplay and graphics, I kept on reading low-score reviews and more I read more I wanted to play it... and I bought the whole collection on Vita on physical, and I've been happy with all three titles (China-India-Russia), so I'm happy I followed my nose instead of reviews.
Short answer
It depends from game to game.