Even though they are both in the same building, the Sportsman Show occupies several times as much floor space. There is way more to see at the Sportsman Show. Even if they have some non-fishing exhibits at the show, they still have plenty of room left over to have more fishing related exhibits than the Spring Fishing Show.
A lot of people used to mention the difficulty of getting downtown and parking as a reason to attend the Spring Fishing Show instead of the Sportsman Show. Now that the Sportsman Show is in the same location and also has free parking, there are fewer reasons to attend the Spring Fishing Show.