I never tried atx and smart thumbs but dont think you can go wrong with them. I have in the past used auto gallery sql, comus for managing the galleries and out of those 2 I liked Auto Gallery the best. Comus wasnt bad but just where a bit to complicated toke a longtime for me to just learn a little more then the basics.
Regarding the traffic trading scripts the only script that I have really used to a lot is TM3 and I didnt like it at all due to several reasons. I also dont think the support was the best.
I have heard a lot of good things about atx and I am myself going to use atx on my sites that I am working on now. Hope my post helped you a bit.
