I have the rx3115 and many HP cameras (between home and office.) We found the 4GB cards to fail in all the products except non-HP devices. The 2GB cards worked in not only the rx3115 but all the HP cameras (home and office.)
I'd get it.
I am buying an HP iPaq rx1950 and I wanted to know what kind of memory I could get to go with it. I know it takes SD cards, but is it compatable with 2.0gb SD cards?