I have always used Booking.com and decided to hive Hotels.com a try since I stay in a hotel on average once a month and figured the accumulated stays for a free night would be worth it. I was wrong. The FIRST time I booked with Hotels.com they screwed up my reservation. Long story short I changed my reservation from two night to one night via the app and changed my room style. I then received an email from Hotels.com asking how my check in went, but the email arrived on the day I originally was to check in and not the new date. So I tried calling and there was no answer for an hour. So I decided to get in my car and start driving in the middle of the night to make use of this hotel room I was now paying for. The next day I called and finally got through but the representative said there was nothing I could do because I stayed in the hotel that night.
Id like to add that Ive NEVER had an issue with Booking.com and Ive used them for well over 50 bookings in North America and all over Asia.
Russgaschick1980 about Hotels.com: Book Hotels & More, v5.2.5