I'm going to answer your title question first because the rest of your post is a bit harder to answer. I take clonazepam and Effexor. It's hard to say which one is more effective. They both help with anxiety. I don't think either one would be adequate w/o the other.
Like you I take a small dosage and have no worries about addiction. I was prescribed Xanax once but it did nothing for me. I've taken Prozac but not the other two you mentioned. Prozac made me edgy. It helped with depression and maybe a bit with anxiety eventually but when I started the Prozac I was glad to have the anxiolytic to take the edginess off as well as helping with the anxiety.
I'm not sure what the medical profession's take is but I think prolonged severe anxiety can cause depression. So I suppose I believe that the Xanax is more helpful.
I don't think there is a perfect med but clonazepam is the best anxiety med I've taken.
Ideally talk or behavioral therapy is the best solution. I have big doubts about the truth of that though.
I hope some part of that was helpful