The biggest difference between the 890 and 890 Pro is multizone capability. The Pro can have 6 rooms or zones (or secondary 890 Pros in any combination up to the total of 6), 6 RF extenders, and 20 (or more) Z-Wave lighting fixtures in the same user account. Note that the Pro does NOT come with the extender unit in the box, it's an optional accessory. The lighting fixtures are considered separate from the 15 device limit.

The Pro also can retain the extender information in its non-volatile memory (you probably need to call tech support to walk you through this). Previously, if you had a power outage, the extender could lose its programming, necessitating a reconnection to the USB cable. Now you can save that data in the remote itself, and just hit 'connect' on the extender to restore it after power loss.