Reservation systems.

I am in the process of trying to get a small 40-50 bed backpackers off the ground and am needing some insight into how hostel reservation systems work.
Which, if any, automatically link with the major booking engines allowing up to date room availability to be shown without timely manual input being required from hostel staff?
What are other users experiences with the multitude of reservation systems that seem to be out there?

Any help is greatly appreciated

Mike