I have never heard or never had myself any problems with sleep on Linux laptops and i'm using Linux(Arch, Debian, Lubuntu) as my only driver for past 10 years
Well, on Thinkpad (which, unlike many, is actually intended to support Linux users) you have to specifically charge something in BIOS to make it work, so one at least has to be aware. Also, I have some old Asus lying around, which after some update started having a lot of trouble with both going to sleep and waking up. Never figured out what it was, I didn't really need it anymore, so now it's just lying somewhere in the closet, maybe will use it for something someday.