We have 2 shihtzus, besides Payton, and my little male would be carried around all day in your arms if he could. He is definately a "lap dog".
I think the only down side with them is the grooming aspect. $50.00 every 6 weeks. (thats for 2 dogs) but on the upside to that is THEY DON"T SHED!!!
Both of ours are very well potty trained too- check out my gallery if you want to take a peek- they're sure cute! (and they get along very well with Pay!)