I recently emailed them to ask if there were any hardware changes pending. Here's their response.
BTW, I have ordered one!

-----Original Message-----
From: KEN HEARD [mailto:kenpcfl@worldnet.att.net]
Posted At: December 26, 2001 3:02 PM
Subject: Question before I buy...

Before I order the remote, please assure me that there is no pending
hardware change of the remote itself in the next 6 months.
Thanks, Ken

Response:

Hello Ken.

There are no hardware changes pending. The Harmony Remote is fully
functional and we have been very happy with its performance in the
field.

Thanks for your interest, and I hope you choose to give the Harmony
Remote a try.
The Harmony Team