Same here. I've read filtered and unfiltered reviews and my conclusion is that Yelp does a good job with its filtering. It's not perfect but does a pretty decent job.
WRT your problem: Have you tried filtering by price ($, $$, $$$)? Perhaps if you did this, you would find good restaurants that aren't just rated highly because they are cheap.
On your last point, I disagree. I used to think that only bad restaurants would need to advertise. But then I ended up going to a restaurant that I saw had advertised heavily in the past on Yelp. I went there because they were in my neighborhood. The restaurant and food were absolutely fantastic (which matched their overall rating). So advertising is good for 1) new restaurants and 2) residents who don't know all the restaurants in their neighborhood.
WRT your problem: Have you tried filtering by price ($, $$, $$$)? Perhaps if you did this, you would find good restaurants that aren't just rated highly because they are cheap.
On your last point, I disagree. I used to think that only bad restaurants would need to advertise. But then I ended up going to a restaurant that I saw had advertised heavily in the past on Yelp. I went there because they were in my neighborhood. The restaurant and food were absolutely fantastic (which matched their overall rating). So advertising is good for 1) new restaurants and 2) residents who don't know all the restaurants in their neighborhood.