For most visitors the best Perito Moreno boat trip is the Safari Náutico with Hielo y Aventura: an hour in front of the south face, sailing all year and in rain, with no age limit, which leaves the rest of the day for the walkways.
If you want to walk on the glacier, take the Minitrekking with Hielo y Aventura, ages 8 to 65, with about an hour on the ice. For several glaciers in one day, Glaciares Gourmet adds the Spegazzini and the Upsala channel to the north face. On a day you already spend at the walkways, the north face boat from Puerto Moreno needs no extra transfer.