I am currently the commissioner of another strat league, in which several ARBA owners (Eric, Tom, Jon, Joe, Josh) also play.
We have three vacancies this offseason if anyone is interested in joining.
The other league has no minor league system and no salary system- once you own a player you can just keep him for as long as you want.
The two big differences between the other league and ARBA are:
1) MINIMUM USAGE REQUIREMENT- in order to be eligible to keep a player, you have to use him at league 65% as much as he was used in real baseball. This leads to a fair amount of strategy when it comes to players who were less than stellar in the last MLB season but who are presumed to have futures.
2) ROSTER SIZE- we have a 35 man roster but only 25 of them are active for a given Series (until the end of the season when we do something analogous to September roster expansion).