what is the best air filtration system for wood workshop?

Answer 1

Is this ever a loaded question. I personally like the ones by Delta. Jet makes some good ones also. Which models you want depend on your shop. How many square feet. All of the units are based on this one thing. I have found that what kind of tools you use, whether or not you have centralized dust collection, and what kind of materials you work with make a difference.
Start with the square footage. If you have effective centralized dust collection, get one unit smaller. If you don't buy it instead.
If you rip a lot of wood on the table saw, use a lot of routers, shapers, sanders, etc get one unit larger. If you do a lot of turning on a lathe, and occasionally cut with a hand saw go smaller.
If you cut MDF, you need one monster machine, similarly for concrete fiberboard.
Good Luck!