2 more cents to add.

The 3500 and the 5000 allow for 12 volt DC triggering of the switched /timed outlets.

I also saw a visible difference in my cable reception when passed thru the 3500.

After having gotten the 3500, cause I couldn't get a 5000, I would like to get the 5000. The ability to assign each pair of outlets appeals to me.
I just wish there was an extra pair of outlets that you could assign filtration to.