I've been put off from buying Catherine, or at least partially, but only because he said it was really hard (yeah, I know but I suck at puzzles and timed, really hard puzzles would just make me want to break something), however I'll still probably get it anyways when it's really cheap or something.
However, I bought Dragon Age 2 after watching his review (note: after as in time after not on-the-advice-of after) and thought it was good so yeah, I probably wouldn't be put off from buying a game simply on what he said unless it was something like really hard difficulty or really bad gameplay he was talking about, not minor issues with the game.