We have 2...both Chuxaway. They have a timer rather than the light sensor as I don't want my hens out at 4am in summer when I cant keep an eye out for Foxy-Loxy. The timer is a bit over-complex as it lets you open/close at a different time every day: Why?
Anyway, they have an aluminium door too. And a really good website with films on how to install.
Automatic doors are not cheap but they certainly make life easier, IMHO.
One thing we found is that a lot of coops aren't configured to allow you to install an automatic door easily, especially the cheaper small ones. You need a clear area above the pop hole of about 18ins to enable the mechanism to draw the door up. Our original coop wouldn't accommodate one so its now just used as an isolation coop. So check whether you can fit one to your coop