I never use Booking. Once got a terrible (and overpriced) location that was highly rated according to them, but above all - I more than once arrived only to realise my booking wasn't there.

On top of that, I hate their UX.

My first go-to is Hotel Tonight mobile, which shows how interfaces should be handled. It doesn't handle rebookings and room selections though, so I often book through a given hotel directly - usually better interfaces than booking - even if not standarised, and I had a better treatment at least once, because I booked directly.

Also, if I type in a hotel name, I want to go to the hotel website, not a middleman. Hotel's website is a proxy of hotel quality to some extent.