dalefan, I commish 3 progressives....I very seldom play a theme. The building of your team through drafts and trades are a highlight. Rivalries and bragging rights are fun. And that you can play through different eras as you progress to give you a chance to manage a bunch of different guys. One I commish is in 1927, one in 1965, and one in 75. My advice is to find a progressive entering into, or just into, your favorite era, and join. commit yourself to five seasons to get a real feel for the league and what it takes to build a team. I don't believe you will regret it.....and a bonus is you stay away from the sharks who build with the same "cookie" players in thems at the expense of newbies.
Have Fun!!!!