Miller signs are great, and I hate batteries! Mine all run off small wall transformers that are controlled from a computer that I use for my night time and storm sequence.
The signs use a PC board that has a pushbutton for you to select the proper sequence of effects for your particular sign. I think there are something like 33 or so different settings the board can output. Some make the sign look pretty goofy and one, or maybe more, will be exactly what you want. The really neat thing is that the board will remember the last setting even with power removed so you can pick the correct setting, install the sign then forget about it.
I would have to say that, of all the things on my layout, my Miller signs garner the most ooohs and aaahs from visitors.
You won't be sorry!
Terry