They seem biased to me. A friend of mine who's doing an ICO told me that they paid 10ETH for 5 quality ratings and that's that! I noticed that some ICOs with good project, team, and good social media presence are struggling with getting good reviews.
With all that said, should it still be a factor to look at when investing in ICO?
No doubt this factor is important but not the most necessary one! I always watch rating in Icobench which helps me in making decisions. Ofc, I trust Icodrops which seems to be still incorruptible, and most projects having highs ratings always succeed in the market!