HI Marybeth,
This is one mighty-tough question; both are great places to stay. However, I think it will come down to which is most important to you: extra amenities or extra space.
At the
Boardwalk one-bedroom villa, you will have 712 sq. feet with a bedroom, bathroom, living room/dining area, and a kitchen. You will also have a washer and dryer. With this resort's location, you will have easy access to the Boardwalk's evening activities and be a short walk to Epcot. You can also take a longer walk to Disney's Hollywood Studios.
At the
Grand Floridian, you will have 440 sq. feet room, but you will also have full service concierge services available to you which include assorted food & beverages offerings throughout the day as well as concierge staff members to help with your vacation planning. You can also participate in the Wildlife Discovery Excursion (a 90 minute private safari ride at Kilimanjaro Safari for an additional cost). The Grand Floridian is also a short boat or monorail ride to the Magic Kingdom.
I'd encourage you to explore the above links to see which meets your tastes/needs best. You might also want to explore www.allearsnet.com for more pictures.
Regardless of what you decide, I think both resorts will have their own unique offerings that we be equally magical!