I would say Vaxholmsbolaget which is (mainly) a local transport operator whereas Stromma is s tour operator.
Correct but Strömma also owns Cinderella and they have a few boats that competes with Waxholmsbolaget on the most popular routes. Including Stockholm-Waxholm. Usually more modern boats, Slightly faster but also more expensive, I would say not worth paying extra for the short trip to Waxholm mayby worth considering for longer trips, like Sandhamn.Edited: 04 July 2018, 16:30
If it interests you, you might want to travel with one of classic ships at least one-way.
Extract from Waxholmsbolaget’s website:
“Travel with our classic fleet
Enjoy a journey on one of our three classic vessels, all built over 100 years ago, but still going strong. They offer roundtrips in the mid area of the archipelago, usually stopping at the picturesque town of Vaxholm both on the outbound and inbound journey.
The vessels Storskär and Norrskär are steamships. Västan, which is the oldest of the three, is transformed to diesel engine.
If you start your journey in Stockholm, the home port address is Strömkajen, just outside the Grand Hôtel and the National Museum. You can go for the full roundtrip or make a stopover at Vaxholm.
Tickets are bought onboard.
There is a cafeteria on all three vessels, and Storskär and Norrskär have onboard restaurants that serve lunch and dinner. Table reservation is advisable.”