I have repeated with both, Kara is the tinny little spinner Jessica is taller but also skinny and awesome body.
Both lots of fun to ride, service got better for me with repeat visit, especially Jessica, so hard to decide which one to choose when I need this visit.
Kara does not smoke for sure which is one thing I really like. She does have very limited availability, and I learnt best to book with her is one day in advance.
From the ad I got the impression that Kara is the unexperienced student and Jessica is the pro, also pics (which too good to be true but surprisingly real) suggest that, however the service I got was the other way around, Kara the student has more routine and I was able to finish with her with CIM for extra, however Jessica did not agree to CIM.
Both don't do rim jobs (in case you are into that), I guess they are too young for that.