I've been doing this for years now, it works even better for niche products (or not massively produced). The last example was the Smarthalo, a friend of mine asked me what I thought about it as I'm into biking, I had seen some ads and their Kickstarter campaign but didn't give much thought, the only way I could find reliable user reviews was by appending "site:reddit.com" after my Google Search as the other user reviews would be from Amazon or other e-commerce websites that I really don't trust.
Yesterday I wanted to buy some inear headphones on Amazon and the user experience on the site itself is abysmal with countless no name China wares and suspect reviews.
A search on fitness related subreddits what people actually use and how (water damage through sweating seems common) was much more useful.
You can weed out the fake reviews on reddit better than say on amazon because of other users.
Just use some common sense and if you see an echo chamber subreddit then take the review with some salt.