I use the aluminum. But I know some people have a problem with it so...
Using a pasta pot with the strainer insert is a good alternative.
This is pretty coold but note that the legs on the bottom of the insert aren't that long so not a lot of water in the bottom...
Steamer #1
I saw this one in store and wanted to take it home. My wife talked some sence into me. Its HUGE.
Steamer #2
This one is nice as you use your own pots and just insert. I have used this one before. This one is very large but you can go elsewhere on the site and find smaller. I like the large as it lists its maximum size. You could always collapse it a bit for a smaller pot.
Steamer #3
This is the steamer I use but it is aluminum.
Aluminum steamer