If this is a good example of what is available at that site, I am not impressed. Beyond lower price, I don't see any advantages to single-hose models unless there are toxic fumes to exhaust. They are very inefficient, yet the site offers this:

*There are pro's and con's to each the single and dual hose applications. If you are uncertain about which unit to purchase, remember that some of the dual hose systems can be modified very easily to become single hose portable air conditioners.*

I have a single hose unit that is supposed to vent the air outside but there is no way to seal it so it doesn't come right back in without extending the slinky pipe. The only thing that really helps is using flex duct to get the outlet way away from the window or wherever you are at. I sometimes sit in front of mine when tinkering with a project in the garage in August or when watching the grill/smoker. It has a moving vent louver that if two people sit in front of it on the deck conversing with ice cold refreshments it just don't get much better.

I have to say if your not sitting really close to the air flow it isn't much to scream about. With two air hoses it would be a lot better unit.