this site says it has cheap airfares. but they are higher than most other discount sites i.e hotwire,priceline and so on.

This really just depends on what you're looking for. Sometimes the discount sites are cheaper, sometimes military to go is cheaper, sometimes buying direct from the airline is cheaper. For us, military to go may end up being a better deal, because some of the discount sites don't deal with foreign flights. So it just depends on what you're looking for (and your flexibility with travel dates).