We used to use an agency and still do for events and large bookings where they work welll but we stopped it for single room nights. We have everyone a budget and allowed them to pay over if they wanted to. We then did a monthly scrape to see where we stood. We got a few escalations and requests but it worked well with an internal TripAdvisor market developing for most of our offices.
Sometimes the agency would save €20 on the room only to find the taxi in the morning was twice this. The benefit of being able to book a posh room and take the missus but claim back the base rate got us a little love.
