That depends on when you go, and when and where you go outside. My mother is in the western U.P. Black fly season is bad - however, at the Lake Superior beach with a nice breeze off that giant lake, not so bad. The beaches of the western U.P. from Ontanongan up to the tip of the Keewanaw Peninsula are a rock hounds dream come true! Fittingly, the beach a mile down the road from my mom's is called Agate Beach and I've spent happy hours combing through rock there. Horseshoe Beach (Falls?) is another icon place up there.
But the lower peninsula has scenic beauty, too. The AuSable River is (was) a great canoe/kayak river with no white water. There are several dams to portage around. I haven't been up there in years - but I do remember the last time we put in at Alcona Dam, the staging area below the dam was full of zebra mussels.
Lake Michigan beaches are just gorgeous - around Grand Haven the sand is incredibly soft. Up north from there you'll find the Sleeping Bear Sand Dunes, and Traverse Bay. Just beautiful!