I've already ordered the MX500. However, I got to admit the Harmony SST768 is quite appealing. The activity centered approach is very attractive to me and would be to my spouse also. I also like the fact that it's programmable using a website and uses an XML database structure. And it's not terribly big. I am looking at the size of the MX500 -- it's huge! I may have to get both and evaluate them.