A review's not just a review, and that's that: a review has an angle; a philosophy; a purpose.

Is the film good art? Does it approach the sublime? Does it achieve what seems to have been its goals? Will it probably please most viewers? Separately, and maybe very differently, will it probably please its intended audience? Does it seem to have an intended audience, in that you can imagine any group of people it might be intended to appeal to (seems funny, but some films are bad in ways that make it hard to even discern what this might be)? Is the craft itself particularly skillful?

A good reviewer will make it pretty clear—if not in the piece itself, elsewhere that's accessible—which of these is playing into whatever final, concise rating they give, or to the overall tone of the review, and it can be totally valid to base a review in just some of these criteria—in fact, it can be hard to cover all of them in one piece without creating an unreadable, confusing mess, and then someone's still going to demand some boiled-down star rating or whatever at the end, which could mean any number of things and is nearly worthless without context.

There are whole books and courses about how reviews and criticism work, including those intended for a wide non-academic audience, what their purpose is, how to approach them, how to structure them, et c.

Ebert is a great example of a reviewer who largely tried to meet films on their own terms, with the result that, if a movie looked like something you might like, and Ebert gave it even 2 stars, you'd probably like it well enough. If it wasn't normally something you'd like or didn't immediately look appealing... well, you better read the review, even if he gave it 3 stars. That made him an excellent reviewer for a broad audience, but it doesn't mean his approach was the only, or most correct, one (not to downplay how good he was).

[EDIT] Haha, all of which is to convey that I agree with you, and expect and want very different things from a professional reviewer vs. audience reviewers.

Ebert was one of the last real effigies of good reviewing. The folks who took over after he died haven't really done his name justice.

That said, I think "reviewing" took on much more than what Roger Ebert stood for. I don't think he saw himself as a gatekeeper of quality as much as someone who could put the summary of the experience of watching a movie in text quite succinctly. Nowadays with things like rotten tomatoes, it literally is a rating, and it's definitional gatekeeping.

If it's gatekeeping, it's not doing a very good job. Star Trek: First Contact had a 96% rotten tomatoes rating a few years ago. It's gradually dropped a bit since, but seems a bit high for that movie, compared with all other movies ever made.

This is the whole point of reviews I feel - you get to know a reviewer and you can use their review to decide if you want to see it. They may absolutely hate the movie, but the way they hate it makes you know you'll enjoy it.

"Review aggregators" have killed much of that I feel.

I assume there's also been a fairly dramatic falloff in professional reviewers given the state of newspapers. Not that people writing reviews as a hobby or as a twenty-something working for pennies for the "exposure" can't do a good job. But you're probably going to get a lot less consistency if nothing else.

True, back when newspapers were a "every city has one or two" there'd often be a local reviewer writing for that paper. Then it went to syndicated reviews and now I'm not sure I can even name a single reviewer.

Also, you have access to much more information about a movie if you want it, instead of having to figure out if you want to see a movie based on three inches of column.

If you found a professional critic that you understand that might be. Otherwise with a random critic's assessment I don't know more than an aggregated audience score. I guess the equivalent would be a weighted score preferring other users that have rated movies you both watched similar to you, as some sites do (such as moviepilot.de).

As the OP shows, horror movies are not for everybody and few professional critics seem to like them. If I like them, I think it's hard reading a reviewer's opinion who does not like them helps me finding out whether I like the newest horror flic. They most probably will not write about what a typical genre movie make good, but why they don't like time in general. An extreme example is https://www.polygon.com/2015/6/1/8687867/rock-band-4-preview

On the other side, a critic who likes movies such as https://youtu.be/uNg13Ju5HN8 is a sure sign for me to stay away from it ;-)

Yes. With Ebert you always knew what his particular filter was (he would usually tell you directly, as IIRC with the LOTR movies he said he hadn't read the books) and you could adjust your expectations accordingly.