On the likes of Yelp/TripAdvisor/Amazon/App Store? Absolutely not, those are relentlessly gamed. I typically look for product reviews on Reddit these days by searching “product_name site:reddit.com” on Google. They tend to be more honest, have more relevant details, and/or suggest alternatives that you can further research.

I would say that they influence my behavior more than many other forms of advertising, but I don't necessarily care about them.