I just switched from the MX-500 to a Harmony One.  I'm pretty happy with it, with one exception.  When I use it with my Comcast cable box there is about a one second delay between button pushes.  For example, when I'm scrolling through my recorded programs on the DVR and I hit the down arrow 3 times it goes down one, waits, goes down another, waits, and goes down the third.  This is a little anoying.  I know it's not the cable box because the MX-500 and the Comcast remotes don't have this delay.  I went into the setup program-> devices-> chose digital set top box-> device options-> Adjust the delays-> and I changed the inter-key delay to 200ms (also the inter-device delay).  I updated the remote but there was no change.  It's still at least half a second delay.  What am I doing wrong?

Try 100ms or even 0ms.

If that doesn't work, there might be some strange extra-long minimum repeat thing going on with the database configuration... try learning a few of the buttons manually to see if anything changes.

OK, will try manual learning of the arrow keys.  That's a good idea.

Also try decreasing the "number of repeats" (now nameless) that Daniel alluded to. It's under "Device > Troubleshoot > Device responds to some commands either too many times or only occasionally".

That helped a little, setting it to 1.  Thanks!

Try decreasing both the Inter-Device and Inter-Key delays to the same low value (100ms or even 0ms) in case the "criss-crossed" and/or "added together" bug(s) is/are still present.

Thanks jlet,
I did try that.  No noticable change.  I'm starting to think it's something with which I'm going to have to live. 

Do you also get this delay in device mode?