I spoke with Dr. Della Valle today and, honestly, Mary....my recommendation would be to go with him. He seemed very confident that he could help you. To me it's also preferable to have him nearby for a couple of weeks to monitor how you're doing. With the other doctor, you'd have to drive that 5-6 hours back to Boston if you needed to see him in person. After all you've been through with that knee you want to do everything you can to give it the best start in recovery that's possible.
I know it will be an inconvenience and maybe even a bit uncomfortable to stay away from home for two weeks. But honestly, you'll be so early in your recovery, you'll be resting and sleeping a good bit of the time. I feel pretty certain HSS has this whole process down pat. I'm assuming nurses and others from their staff will be checking in on you wherever you stay once you leave the hospital. And....in the scheme of things....it's only a couple of weeks. You'll have the rest of your life with this new knee!
Pumpkln had a good idea for you to write down the pros and cons for each choice. Maybe that will help you decide.