Zardnaar
Legend
Or, alternatively (and, I think more accurately) folks may be rating in terms of how much fun they had, or expect to have, playing the thing. If they think it'll be a lot of fun, it's worth a 5, no matter that there's some that may be technically better designed.
There's a restaurant near me. They sell burgers. If I take one apart, and look at each piece with a very critical eye, I am sure I could come up with a laundry list of negative aspects to the burger. Tallying a review on this basis will make it look like their food is awful.
Stack the stuff together, and take a few bites, however, and the burger is awesome!
People on messageboards tend to do more of the former, and less of the latter.
I prefer more a % based system on reviews. For example a lot are simple yes/no.
On a % system anything higher than 51% could get a positive tick even though I consider 51%-70% as a bit meh and anything below 50 as outright bad. I don't generally buy video games rated below 70% for example.
Giving HotDQ a 5star rating is silly IMHO along with a 1star rating. I trust the ENworkd reviews more than Amazon and I buy stuff based in positive buzz here more than say Amazon. Also try and avoid Amazon as much as I can due to RL moral reasons as well (labour conditions).
Some things are also very very subjective beer and wine reviews are prime examples. D&D adventures are a lot easier to rate IMHO.
5E adventures are fairly consistent though none are really bad and most would be in the 65-85% range with a few standouts.
It's impossible to crank out consistently great APs IMHO. Great adventures tend to be shorter as it's to hard to keep things going over 10-15 levels.
Each on is essentially 3-4 smaller adventures and no author yet can crank out that level of quality consistently.