Geesh, I love my collareds have over 25, they are all pets and very tame, I love them for that reason in particular friendly, but they are very active and fun to watch. And the other major thing that attracts me is their BEAUTY, whew, so diverse in color, species.
Chuckwallas on the other hand can also become quite friendly, and have personalities with ATTITUDE which I find funny, and enjoyable. I guess I like a little bit ornery STYLE ! 
They just amuse me with there ways. Theres nothing more rewarding then to watch a chuck eat, they really DIG IN, and throw stuff, stand in the bowl, big chunks of food hanging from their mouths, NO TABLE MANNERS WHAT SO EVER, But I get a kick out of them.
My iggy was adopted, and it has taken me a LONG time to get him friendly. He trusts me finally after a couple of years. So in my opinion the others were more interactive. I do really like the desert iggies, they look awesome, good looking lizards. But nervousy IMO.
Why do you think I have so many species of lizards, heheheehe I could NOT MAKE UP MY MIND ,

Good luck with YOUR decision. GET ONE OF EACH ! 
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Eve / PHEve