I think its safe to say that users reviews can be a collection of written hot garbage if implemented poorly. Thankfully, Valve has found a creative way to make user reviews more reader and human friendly.
This system that is currently in beta works simple enough. Before you can express any written criticism about a game you must own it! Next you would have to had launched the game at least once. When you do write your review, your playtime is displayed right next your evaluation. This seems to be a good way of telling the difference between a thoughtful thoughtful and merciless trolling. No word on whether or not they implement any sort of scoring system.
The Recommendations page has been converted to Reviews. Below is a screencap of the review page for XCOM: Enemy Unknown.