Hello Bella,
Good to see you tonight.
The main differences between Xanax and Klonopin is their time to peak plasma level, and their half-life in your body.
Xanax takes 1-2 hours to reach peak plasma concentrations, and has a half-life (i.e half of the available drug has been metabolised) of 9-20 hours.
Klonopin, conversely, has a 1-4 hour peak plasma time but a much longer half-life of 19-60 hours.
So, therapeutically speaking, Klonopin would be the main benzo for your condition, and Xanax could be used ONLY when you were having "breakthrough" panic attacks to supplement the benzo effect, but clear your system more quickly.
Be sure to discuss the choice of drugs with your physician if you have questions.
Take care and remember I am not a professional.
Hugs
Kitt