They have also been bad with their ratings at times when high quality of the project was very obvious. In that case they probably did an independent rating. Question remains whether they take money from some projects or not but I doubt that we will ever find out.
Definitely questionable and the biggest issue is that you should always assume they bought the coins they are talking positively about to then sell them after you read their ratings. Not very good.
I personally look through some sites with ratings from time to time. But I don't completely focus on them because not all ICOs with high ratings are guaranteed to be successful. I rely more on the team, the telegram, wp and so on
That is the way to go. Once I witnessed the ICO that has a very good rating from Icobench but they failed to reach their target even the softcap