Thanks for all the feedback
To be honest, I'm not sure how my cats will behave in a new environment - they're quite friendly, and behave comfortably with guests around, but it's not like I have people over everyday. I'm more inclined to choose pet sitting at this point. Newt has a very relaxed demeanor and I think she'll be fine, but I can imagine Newton getting restless without sufficient stimulation.
The kitten is chipped, but not his mom (I'll get that done eventually). I wonder if I'll get charged extra if the cats dash out the door, and the sitter has to spend 20 minutes chasing them around and get them back inside?