Do some googling.
You will see one thread after another of complaints. Plus many threads or posts where good service was gotten.
YMMV
Most of the complaints were of two kinds.
Reservations changed after being paid for but before the trip started.
People showing up at a hotel for a pre paid stay and finding out they have no reservations at the hotel.
I assume based on the vast number of posts both views have merit. You can save a bundle. You can have a nightmare of a trip.
It may work out for you. It may not work out for you.