The only corded circular saw I have ever owned is a Skil brand saw. I still have it some 50 years after I bought it (haven't used for at least 30 years though).
My circular saw of choice now is a Dewalt 6-1/2" 20v. The model number is DSC391. The one before that was the 18v version (model DSC390, I believe).
I prefer the cordless versions, they are far more practical. Since they are more general purpose for me as a DIY'er, it doesn't get used that much.
Until a few weeks ago, I thought all circular saws were generally the same. I know there are some differences in quality levels and usage levels. For example, a carpenter working on rafters would likely use a heavy-duty worm-type circular saw. But, I was not aware that there are circular saws with the blade facing left (known as left-facing) of the handle and some with the blade facing right of the handle (known as right-facing).
I've done some research on this. It seems that all corded circular saws have a blade that is right-facing. Cordless circular saws is where it's different. Quite frankly, I don't know why there are left-facing and right-facing. But, I do know which is best.
That's how I came to this point. My Dewalt DSC391 is left-facing. I had a project where I used my Dewalt saw extensively. I made a saw guide so that I would end up with straighter cuts. That meant that my guide would have to be on my right side. I'm right handed, which means I had to use clamps to secure the saw guide since I could not reach over the running saw to hold it – and still have sight of the cut line and blade.
The next issue I became aware of was the material I wanted to keep was to my right and unsupported, while the scrap was on the left. Supporting the scrap material put my hand and fingers in jeopardy all the time.
Those two issues are enough to get me to switch circular saws.
At the same time, I am considering an increase in blade size - from the current 6-1/2" to a 7-1/4" blade size. I'm sticking with the Dewalt brand. That means I am looking at the DSC570 and DSC573. I'll likely pick the DSC570. It's a right-facing blade and a step up from the basic DIY saw.