I would agree I think booking through a lot of wholesalers like that are a gamble. I think they have their place in the travel world. But with that lower price does come risks, such as not having control over your own vacation, cancellation, etc.
I have used some in the past such as hotwire for car rentals and been very happy. But it pays to be on top of it and keep all paperwork handy, and read the fine print.