Challenge: B+. If you opt to make your own team, it's a long road to greatness. You start out with crappy players, who need cash to improve. Getting cash means beating the good teams with bad players. On top of that, the computer almost never makes an error.
Graphics: B–. The in-play graphics are surprisingly average, except for one thing—the outfielders are large. It's easier to catch fly balls this way. The "cut-scenes" (home runs, firing a player and such) are pretty good, although they're no Ninja Gaiden.
Sound: B–. Energizing music. It changes when runners move into scoring position. It may get annoying when the pressure's on and you're trying to concentrate, but solid regardless.
Fun: A–. The funniest part that I can think of is the fact that there's women in this game, and for the most part, they suck. However, the "Lovely Ladies" team pays off the most during season play. It is funny to hit them with a pitch and watch them bawl their eyes out while sitting in the dirt in their pink skirts. It's also possible to scale the wall to bring back a home run and fall into the stands! Ouch.
Overall: A. One of the only baseball games for the NES worth getting. The fact that you can save games and build teams, and get access to complete stats is a "home run" as well. One of the best ever.