I have been using booking.com for years for hotel reservations and in general have been quite happy with selection of hotels and prices.
But – and here is the catch: Just last knight I realized that reservations made by booking.com are not really confirmed reservations!
They just send your reservation request via mail/fax/phone or what ever and there is no guarantee that you have a reservation when you come to the hotel. If hotel is full, reservations made by booking.com have no priority and all others will be served before you.
I had reserved our hotel in Budapest some 2½ months in advance and when we showed up at the hotel last evening, receptionist told that hotel is fully booked and we did not get any room from that hotel! Instead we had to find another one from other hotel.
Lucky for we had motorbikes to travel, so no did not need a taxi or any other transportation for this purpose.
Have to think now twice if I use booking.com in the future to reserve hotel rooms or not.