I don't have the exact count with me right now, but it's around 10 analog cameras, plus a some IP cameras. More cameras will probably be added in the future so I'd like the ability to handle at least 16 analog cameras and 24 cameras total.
I want a Windows based system for the software and hardware flexibility, the lower cost per camera and quality, and the better/faster interface. I've considered and used dedicated recording units but they seem like a really poor value compared to a Windows based system. If the issue was space constraint then a dedicated unit would make more sense to me since they tend to be smaller.