Queretaro and San Luis Potosi

Does anyone have experience with these two cities?  How would you compare them?

Thanks!

You really need to go vista them in the flesh.you will then be able to best decide.  What please one person may not please another.

I did get a chance to see Queretaro and found it a nice place, quiet, interesting.  But I didn't have time to see SLP, that's why I'm asking.