Hi there... I'm a long-time One4All user (Radio Shack 15-1994 and 15-2104). I've been very satisfied with these; my older unit has finally outlived its time, so I've been shopping around for a replacement remote for my living room...
I ordered a Harmony 676 based on reviews, and after reading many of the laudatory comments in this forum. Unfortunately, I wasn't very satisfied with it, especially due to the following issues: 1. Directional controls: The "ring" seemed very awkward and unpredictable -- because all directions are "connected", I found it very hard to use for navigation; despite being deliberate about where I was pressing on the ring, it would frequently generate keypresses in the "wrong" direction (I have medium-size hands, btw). One of my main components is a media adapter (Squeezebox), so poor directional control is a deal-breaker. (I realize there are other Harmony models with discrete directional keys; I'll favor those layouts in the future.) 2. Key ergonomics: Compared to my RS remotes, the keys on the Harmony seemed smaller, stiffer, and with less "travel" -- a generally unsatisfying tactile response. In addition, I would have preferred more variation in key size (large buttons vs. small buttons) between often- and lesser-used functions. (I can appreciate that key size is probably most affected by the amount of area taken up by the LCD display.) TiVo's "peanut" remote layout is a great example of size-contrast done right, IMO. 3. Updates: The web app was reasonable, but the (Java?) updater felt very sluggish and "clunky", and the update process seemed slow as a result. (Because some keys for the Squeezebox and my DVD player didn't map correctly, I had to make learning overrides several times.) While I could deal with this issue if the updates were fast, slogging through the tweak-update-test cycle many times became an exercise in extreme frustration.
Upshot: I returned the 676. I really do like the Harmony's activity-based philosophy and onboard logic... but a succesful remote should pass a "blind feel" test, and I feel Logitech still has some significant work to do in this area.
Obviously there are many satisfied Harmony users here, so I may be standing alone on this... I'd appreciate your comments, esp. WRT other Harmony remotes I should consider (520/Xbox?). Else, I'll probably have to stay in the device-based land, at least until the activity-based units get better ergonomics.
