Booking . com is rubbish, after making the booking, and receiving booking confirmed on the screen, I later when I checked with the actual hostel, the said no booking in my name existed and booking was not valid. Even booking.com seem to think I was booked there, and I get reminders to review my stay there!
So - YHA is great, booking.com is rubbish. Sorry I am annoyed my booking went astray, and I had to pay extra to stay elsewhere at short notice. Good job I checked with YHA, if only I'd booked direct. Booking.com is so detached from the actual place you want, they have no idea what they are actually booking, and get no feedback to confirm the place exists.
YHA in general