Remember that a tool and a vacuum running on the same outlet or extension cord can pull lots of amps. Most random orbital sanders draw less than 7 amps, but big belt sanders can draw 12 amps, exceeding the tool trigger's ratings. Nevertheless, I didn't trip any breakers during testing with either tool.
To clear the dust from inside the hose, the tool-triggered vacuums here continue to run for a few seconds after the tool is deactivated.
Because these tools span a wide variety of features and designs, it's hard to make a definitive overall choice. The best tool depends on your work and your budget–dust extraction only, remodeling, lots of wet work, etc. For my work, I choose the Bosch. This versatile unit has that great filter shaker, strong dry and wet suction, easy-to-change filters, and a stable design. It would be superb as a dust extraction unit or as a serious shop and site cleaner. It also guzzles water effortlessly.
The Porter-Cable is virtually equal to the Bosch. With a large capacity, low weight, intelligent tool trigger, well-designed drain, and easy-change filters, it's an excellent tool. Only its top-heavy design and slightly lower suction drop it into second place. The Festool has tons of features, plenty of suction power, and a super-stable design. For pure dust extraction, this would be my choice; but its capacity may be too small for big cleanup jobs, and it's awkward to empty if you don't use filter bags. The Fein is quiet, light, and has a good tool trigger. It lacks a blower, tool caddy, and a tank drain, but I really like it for tight quarters, and it's nice for carrying in the truck–a good unit if you're constantly on the move.
But perhaps you don't care about a tool trigger. If all you need is a serious tool to clean the shop and sites, then the big, powerful Craftsman or Milwaukee models might be as good as or better than the models above. On the other hand, the Hitachi will do most of what the others will and is light, small, and inexpensive. The Shop-Vac is also inexpensive and includes a tool trigger and nice tool caddy. The Makita is quiet and well-made, but lacks the power and many of the features of its competitors.
–Chris Kulczycki is a boat designer/builder and writer in West River, Md.