Well I use all three, but I find I make the most money off Infobarrel. Even though Infobarrel's Alexa ranking is a bit lower, it still seems to rank as well if not better than the other two. Just a few things to consider.
I have not tried using squidoo but have used both hubpages and infobarrel. I like the design of hubpages the most.
I like the design of Hubpages the best. It's very easy to add new modules. I've made some very similar pages (same topic, similar titles) on both Hubpages and Squidoo, and hubpages gets WAY MORE TRAFFIC than my squidoo pages.
BUT, on pages where they are buying pages like product reviews or something, I've had MORE SALES on my Squidoo pages. I've just started using Infobarrel, so I can't really compare them.