Should I use Microsoft ATL or WTL for client Com support?

Hi:

It's been a while since I've worked in the world of COM.
I've got a basic Microsoft unmanaged C++ class with some methods I'd like to expose
through COM. There are no activex/ui associated with it; it's a straightforward simple class.

On the client side, I'm a little confused on to use to manage interfacing with the COM object.
Which template library to use: ATL or WTL?

I assume that they both have their own flavor of smart pointers.

Given a brief description of my needs, what is the correct way to go?
ATL or WTL?


Thanks,
JohnB