Touch probing vs Scan probing

Well, they are quite different. Kind of a broad subject actually. 
It would greatly depend on what kind of parts you have to measure and what kind of data you need.
I am just starting to get into scanning now, so far things to note would be that calibration takes significantly longer. Your probes will take much more wear. Small details and the cleanliness of your part matter a good deal more. Scanning features like bores are generally faster than taking an acceptable number of TTP points.   

I'm sure someone else will chime in, but it really comes down to how your going to use it.  

Well, they are quite different. Kind of a broad subject actually. 
It would greatly depend on what kind of parts you have to measure and what kind of data you need.
I am just starting to get into scanning now, so far things to note would be that calibration takes significantly longer. Your probes will take much more wear. Small details and the cleanliness of your part matter a good deal more. Scanning features like bores are generally faster than taking an acceptable number of TTP points.   

I'm sure someone else will chime in, but it really comes down to how your going to use it.  

Thanks, I'll keep it in mind.