We booked an excursion though ShoreTrips on our cruise to Alaska this summer. It was the helicopter and dogsled excursion. We thought they did a great job. Very friendly, on the shuttle back the driver pointed out some places in Juneau we should check out if we had time - a little extra tour guide information.
Also want to mention that communication via email before the trip was excellent. We received several prep emails about how excited they were to have us.