TripAdvisor ratings are very indicative and the portal usually shows prices from various booking sites. Then I call the hotel directly and 90% of time I get a better price and a room of choice guaranteed right them which is not at all possible over booking sites where you get a room type and get assigned one when you check-in. Definitely direct booking when the property is on AirBnb - in this case almost always owners themselves ask me to book directly with them and bypass AirBnb.

You are bang on about the cost threshold.

Pro-tip: for real hotel locations use Google Maps in satellite mode. Esp. useful in hill stations and beaches - you'll avoid hotels that claim to have a view but forget to mention it's the bus-stand view.