The first thing to consider would be location. How far away from where you are is the office? If the vets are the best in the country but it's a two hour drive to get there, you might want to consider something closer. On the other hand, if the best vet in the country is only a 45 minute drive away, or the only vet in the county is a 45 minute drive, it might be worth the trip.
Along with the location, do they do housecalls? If so, do they do housecalls for cats? For some cats (but maybe not all), having a strange person in the home is less stressful than going for a ride to see strange people. Some mixed animal practices treat most of their large animals (horses, cattle) on housecalls; they may treat dogs and cats on the same trip if you let them know. One of the local small animal vets is primarily housecalls only. For the vets who perform housecalls, you should know what they do when surgery or other more extensive treatment is required. Whereas a traditional clinic has a surgery room and an X-ray room, what does the housecall vet do? Do they have a big van that serves as a mobile clinic? Do they have an arrangement with a local clinic to use their facilities?