I have a dewalt 18v 5-1/4" circular saw that came in a kit with drill, reciprocating saw, impact driver, and light. The light has never had a battery stuck in it that I know of. The circular saw is pretty handy and the battery lasts longer than I thought it would. It will cross cut a 2x with no problem. When we resided my shed, which led to almost rebuilding it, it was used extensively.
I thought the circular saw might get a little use to keep from pulling out extension cords etc but it has been used quite a bit. Battery life is nowhere as long as in a drill but I made over 30 2x4 cuts before changing batteries. I cut up some rough saw mill scrap into a (heck I need another) ladder (quick), and not wanting some one else to die using it, finished it later into kindling pieces.
My daughter wanted a 'real cordless drill' and I fell into a deal on a Ryobi set which included a drill, circular saw, reciprocating saw, and the obligatory light... They have not seen the use my dewalt set gets but I don't worry about taking my stuff over now if I go to help on a project. I redid their basement crawlspace access, worked on a shed door, and some other projects using just her set and the Ryobi tools worked very well.
The other cordless circular saw I've used was a Makita. I think the saw worked very well but desperately needed a new blade- no fault of Makita. I can't compare it due to the wheel they were trying to cut with, but I've had good experience with Makita cordless tools in general.
I did buy a b&d cordless drill. It had been on mar down sale for less than $10 and was then marked down to half its lowest price. I knew it would not be great but for literal pocket change I tried it. Not great as a screwdriver or drill - but the thing is perfect for sharpening. I use it for my angled stone on mower blades and to hold the what is it 5/32 dremel grinder for a saw chain. Turns at a SLOW but very steady rpm. I get consistent sharpening out of it. So even though it isn't a fast powerful machine, it is still a decent addition to my tool collection for what I ask out of it.