Not sure I would recommend a dealer. Call around if you want, but pound for pound they've always been more expensive in my experience.
If you feel up to the task, as others have mentioned, it's a fairly simple driveway job, just make sure you have a catch pan or some other way of dealing with 2 gallons of old oil
Any lube shop can handle it as well, just make sure they're using decent oil and filters. If you're concerned about it you can always bring your own oil and filter to most places as well (it usually costs a bit less this way too, depending on their synthetic markup).
On the whole as long as you go with a good 5-30 synthetic and decent filter, you can't go wrong