baseballregie,
You are right, this type of booking is not for everyone. You have to be firmly set in your travel plans.
There are some really great deals, though. Last summer I booked a round-trip through Orbitz from Washington, DC to Ixtapa/Zihuatanejo Mexico for just under $350. There would have been an additional cost for an overnight hotel stay in the middle of each trip, but I had plenty of Priority Club points so those stays were free, and at a couple of nice places, too. It fit my travel plans and budget perfectly. And I found the rate and booked 10 days before traveling.
Once in Mexico, I had a rental car that I had also booked through Orbitz. I was involved in an accident there, but I was smart enough to purchase extra insurance through the website at the time of booking. It took a little while to navigate through the language barrier and the Mexican Dollar Rent-A-Car way of doing things, but I did receive full reimbursement for the damages that were placed on my credit card.
All in all, I was very satisfied with everything, except the accident and one umpire.
...and maybe the rain.