Being a little conservative, I only use 8 port switches. That way if one fails for any reason, I potentially only lose half my cameras. By being creative with which ones are on which switch I can still keep a full view. It also allows enough open ports to plug cameras into from the failed switch. I have no idea if the 16 port has a fan but can tell you the 8 port doesn't. They run slightly warm, not hot, with a nominal load of 11 cameras on each.
I'd stay away from the cheapies. They probably all use marginal power supplies like BVTech does. They're cheap for a reason. As
@looney2ns says "buy once, cry once".