Regarding the question how to judge different reviewing sites or more correctly different review outcomes on different sites...this may be a bit contra-logical since we build such sites to help with quick judgements in the first place but if you want to understand such a site, you should dive a bit into the descriptions, how those reviews or - most of the time - the comparable numbers added to each project (stuff like Marketing: 7/10 points or Team: 8/10 points ) are created. Sometimes the makers of the site make some kind of equation which they apply with respect to all available information, sometimes its more of a group-thinking thing and its just the average result from all global reviews of its members. If you find out how a site does create its numbers, you can also decide yourself, if you think their process is helpful to the kind of decision you wish to make. ;-)
Icobench for example also works with average numbers but since you are able to read every single review which participated to reach this outcome, you can judge the outcome in a transparent way and just disregard singular opinions which - in your eyes - are, for example, biased or concentrating on faults which you don't think are that important.