[gkf9]

How well does the harmony remote work on the shield or are we better off with the stock shield remote you can buy?

It works perfectly. Here is what I have learned you have to do.
When setting up an activity, select Watch Movie, not Watch TV. If you select Watch TV, you will not be able to control the Shield with the remote because it will map the controls to your TV.
The sideways U-Turn button (return) is not mapped. You will have to map this to "Back" manually.

Other than that, it works fine. I have a Harmony 650, a Harmony One, and a Harmony Hub ultimate, and have tested all of these.

Does it work well inside Kodi? And can you tell me what device did you set the Shield up as in the Harmony database?

Tia