Ryan:
I have traditionally used all SSR4/DMXes rather than Expresses because I preferred a decentralized system. In my last show (2011) I actually used four SSR4/DMXes to drive a "midi-tree" (six-foot height, 16 multicolored strings); I have an Express kit and may yet build it this year to take care of the extension cord mess that the four SSR4/DMXes caused.
Like others, I use them to in specific areas -- at one time one controlled three strings on kitchen window, one controlled three strings on the front door, one controlled three strings on the bedroom window and one controlled three strings on the living room window. And, of course, mini trees.
This left me with minimal extension cord ho-ha and a single data cable that daisy-chained around the house.
This also allowed me to grow the show slowly.
HTH.
\dmc