They are both fairly strong shorter acting benzos. With a shorter half life they can be more addictive, but if taken as prescribed, they are a useful tool to use as you talk it through with a professional. I have taken both and had no problems coming off, but remember not to self medicate...only do it with the advice and prescription from your doc.
1mg Ativan = 0.5mg Klonopin = 25mg Librium = 15mg Tranxene = 10mg Valium = 0.5mg Xanax.
So Xanax wins the race. But it is a nasty drug that you get hooked on with ease and can be a killer to come off of. So make your mind up time.