For those interested in adding a keyboard to your Logitech Harmony setup, you'll be happy to know that there is a cheaper alternative to the $100+ Smart Keyboard Add-On.
I tried out two keyboards that I had laying around this weekend with mixed results. The first was the keyboard that came with the Logitech Revue Google TV box. While I've had no problems pairing it with other Logitech Unifying receivers, it refused to pair with my Harmony Hub.
Next up was the Logitech K400r keyboard that I've had for a few years now. The first pairing attempt failed, but it picked it up on the second try. There are a couple of things to pay attention to when looking for a k400r. One is that my version has three media buttons across the top with a pc power button next to them. The newer versions lack these buttons, or they have been replaced with shuttle controls. I can't say for sure if these newer versions will work with the hub or not. The second is that the symbols on some of the keys don't match exactly between the two. They are close enough to not have caused a problem yet.
I have my hub paired with my Nvidia Shield TV (2015) over bluetooth. When using the keyboard with that activity the keys work great for typing in search blocks or passwords into apps. The shuttle controls, volume, and arrow keys all work as expected. Activities and power off mirror the Harmony keyboard, but again the symbols are slightly different. They do mirror the layout of the activities on my Harmony Companion remote though. One thing I didn't expect to work was the trackpad and mouse buttons, but on the Shield TV they work just as if you had a bluetooth mouse paired with it. You get a cursor on screen and can click on icons on the home screen and in most apps. Two finger scroll does not seem to work though.
If you have already have a Harmony Hub and a wireless Logitech keyboard laying around, give it a try and see if you can get them to pair. It's handy to have and might save you some cash!