Fan-Tastic Vent fan can blow into the Rolling Steel Tent, it's mostly used for sucking hot air out. The O2 Cool fan's job is to blow directly on me. That goes a long way toward making muggy days (like today) more bearable.
The O2 Cool fan has a magnetic mount that's handy for sticking it in various places. It's very quiet and doesn't wobble. The lower of two speeds is usually enough to keep me happy. Unfortunately, it looks like they've discontinued this magnetic-mount model since I bought it in 2013.
The Fan-Tastic Vent fan is louder and a bit grating. It can get quite a vortex going in the van when it's on top speed. The annoying thing is that the support arm for the lid has a lot of play in it. So the lid flaps in the wind, making me worry it will break off. And since I don't want one of those bread box sized rain covers on the roof, I have to close the vent when it's stormy. That's when the other fan is especially useful.
I think I'll go talk into the fans now and make my voice funny.