Both boat tours are great.
Soo Locks tour takes you thru one of the locks up bound and later thru the Canadian lock on your return trip.
If you go to the Pictured Rocks, I highly recommend taking an afternoon tour. The weather is one factor, but not my primary one. Look at a map. The Pictured Rocks face into the lake, toward the Northwest, generally. With the afternoon sun coming around to the west, the P R are much prettier with that sun shining from across the water.
Per other comments, there is much more to the UP than just the Soo.