NHL. MLB. NFL. Each of these hold a level of prestige since those are professional sports organizations. We "ooh" and "aah" over how cool we perceive these athletes to be (well, some people do at least). There are many photographers who think they've "made it" when they get to shoot a professional event.
Granted, that's pretty cool, but with that level, comes its own set of problems. In the MLB, you can normally only shoot from the 1st photo well, or the 3rd base photo well. Want to get something from behind the plate of the pitcher? Tough, there are paying customers in those seats.
Going to an extreme sporting event like the Winter Dew Tour or XGames you're told where to stand, where to go, and where you can shoot from. Want to shoot from the knuckle of the jump? Tough luck, only NBC photographers get to do that.
Don't have a 400mm camera? Oopsie, the fields are so big you're pretty much out of luck there.
Having shot some of those events, yes, they're very very cool to shoot. There are media areas with food (sometimes free, sometimes not), people to talk to, and "omfg I'm shooting the Colorado Rockies!" However I'm finding I like shooting the smaller events better.
This past weekend I was up at SolVista Basin for a slopestyle competition (my favorite photo is above). Nobody told me where to shoot from - I could go anywhere as long as I didn't interfere with the competitors. I got to meet the guy that created the terrain parks there and talk with him. I met many of the competitors and interviewed the winner without fending off hordes of media. I could plan my shots to minimize background interference as much as possible (really hard with lift lines and lampposts in the way), and score some cool shots. In fact, I probably didn't even necessarily need to ask anybody if I could come shoot, although I did as a courtesy thing, and it was very easy to find whom to talk to beforehand to ask.
In the fall I shot high school softball. Were there parents sitting behind homeplate? Yes. Did I ask them super nicely if I could get a couple shots of the pitcher and possibly block their view for a couple of minutes? Yes, although I didn't end up blocking them since I was on the ground and they were in the bleachers.
I think everybody is concerned about "if I don't shoot professional sports, I can't get that killer shot." Untrue! While it may take a little more effort since little Timmy doesn't dive for the soccer ball or "bend it like Beckham" every play, the opportunity is there. It still is cool to shoot professional events, but don't knock the amateurs where the access is better and easier.