I bought this remote because my home cinema amp did not come with one (ebay bargain) and a new one was going to cost 20 quid, so thought I might as well pay a bit extra and get this to replace all of my remotes.
The device is programmed by plugging it in to a pc via supplied usb cable and using logitech's web site to add devices. You enter the brand and model of each device then sync with the remote. I had problems with this immediately.
The instructions will tell you to go to a site that uses some sort of silverlight/flash interface to program the remote, this service is flakey and I could not get it to work at all. Firstly one of my devices was not in their database so I had to teach the remote the various commands, after pressing all of the required buttons the site just hangs indefinately. I tried this 3 times with no success. So with only 2 of my 3 devices added to my account, I attempted to sync the remote, again this hangs indefinately.
Fortunately I found a solution. There is a peice of software that you can download from logitech that performs all of the functions of this site, but that actually works, (google 'harmony remote software download').
After adding all 3 of my devices, TV, amplifier and dvd player (that had to be 'taught'), the remote works perfectly.
The functionality is great, you can programme activities such as 'watch tv' or 'watch dvd' and the remote will turn on the relevent devices and switch the input on the tv (I also get mine to change the input on the amp and the surround settings). It will also control the volume on the amp rather than the tv.
You can switch device control at any point and any buttons that arent physically on the remote will appear as soft keys on the LCD.
Another nice touch is that the remote lights up when you pick it up.
I am very impressed with this remote, there is not a single feature that I cannot access on any device and this remote makes it much simpler to control everything without numerous remotes.
If it werent for the initial hiccups when trying to set up, I would have given it 5 stars.