Userspace or kernelspace driver once again

[Patryk]

Suppose that you want to use a driver that controls fans ,let's say
max31785. You have two options to chose:
- kernel space driver that is already available in mainline linux
- userspace driver that comes from Hardware Abstraction Layer library
that also has an implementation, the library is a primary hardware
access library used by all our projects

What would you choose? And why? And if "it depends..." then depends on
what actually?

Best regards

Patryk