Personally,  I don't like to book my hotels via on line booking
engines because as a business traveller I find there is little
flexibility,  as total pre payment is often a pre requisite and I
often need to change plans last minute.To try to get your money back
is a nightmare and too time consuming. I am far too busy for that.
However I found a great web site offering not only great rates but
"personalized service". Yes I deal with a person and they are really
efficient, prompt and the savings are good. They cover the whole world
and the staff really do that little bit extra each time.  If you want
to deal with a person  and want reliability, and great rates as well
and don't want to pay in advance then I really recommend these people
(and I mean people !)  Their site is: www.abt-travel.com