I own several circular saws. A Skill HD77 (difference between that and the mag one, to my knowledge is color and two pounds), a Bigfoot (Skill 77 motor with a 10 1/4" blade), a Bosch CS20, a Porter Cable 424, and a DeWalt (I still spell it the old way from when they were good), DW384.
The Skills, Bosch and Makita worm drives are all good, although my preference is to the first two. Most roofers I know will only use a worm saw as they last, are durable (falls) and fairly rebuildable (just a mater of finding the parts locally as they don't want down time). But they are heavy.
For non construction or things like furniture/woodworking, I prefer the lighter weight of a sidewinder and I prefer a braked version. I tend to use these with my guide system (Eurekazone), and haven't used the tablesaw in some time.
In Canada, there are restrictions by their version of OSHA (at least commercially), that a right bladed saw, (sidewinder) be used by a right hander, and a left bladed sidewinder be used by a left handed person. The motor is supposed to be a safety block and your to use the notches in the base plate as the guide (or things like a sawboard).
In the US we don't have those restrictions, and I am unclear as to Canada's take on the worm drive.
Sidewinders with brakes stop faster, then worm drives, then sidewinders without brakes. But I have seen worm drives that held up/lasted longer (seen some from the late 40's early 50's? or attributed to those periods). Blades DO make a difference, I do prefer the thin kerf Diablo's, that I got turned onto by Eurekazone.
