Having done both, running kennels/cattery and a home pet sitting service (long before it became the latest 'fashion')
I would say for a long period (eg over a week) I would definitely use a cattery. Someone popping in once or twice a day is fine for a few days, but for a ten day period I would feel happier knowing my cats were safe and secure in a well run cattery, owned by people who do it because they love cats. They have to be inspected by vets and be licensed, and if they were not up to scratch (forgive the pun) they would soon go out of business. They will sleep most of the time, or play out in the runs, and have food provided 24/7. They will give any medication if necessary, and call in a vet at the slightest worry (this will be covered by insurance).
Go for a FAB approved cattery as they have very high requirements (google their website for an approved cattery in your area).
It is a lot to expect a friend/relative to take on, and what would happen if they had to go away themselves, say in the case of an emergency, or heaven forbid have an accident and not be able to get there.
Also check out the cost of pet sitting, I think you will find it is not as cheap as you would have thought, and two cats in together will get you a reduction in the cost of boarding.