I have one that is rigged up to vent to the outside, and I love it. It allows me to run my airbrush and use shaker-can primers and sealers year-round, rain or shine. The one I have was made by by Dad and me using some old vent fans he already had; those are the most expensive parts of a custom booth build. In general, I would say they are a good buy, but I can't speak to any of the specific models in your links above.
