I won't say "trust," I'd say I'd pay instant attention to them, especially if they come with a whole block of angry and highly specific rant (yum).
As for a string of 5-star reviews that come from the same succession of accounts that leave generic two-liners on nearly every popular story here... I'm more surprised that those accounts are still only at lvl2 or lvl3 with the exp they must surely have gathered by now.
The 1-star or 2-star reviews for the sake of flaming are simply unfair, even if the sentiments behind them are understandable.
I noticed a confusing phenomenon in my random quests for juicy reviews, though: there are some 1-star reviews where the content is nice and glowing and couldn't be more supportive, then there are 5-star reviews that flays the story to the bones. Wonder what's up with those.