OZ is 40,000 miles within two years and you get *G for the balance of the qualification period plus an additional two years. Plus no "minimum segments on home airline" rule.

On the downside, they also have more restricted earnings tables (many fares do not qualify for miles at all or earn reduced miles) than AC/UA/CO. And using miles is a problem (high taxes/fees and everything is mileage based, so it often costs a boatload of miles for a short trip). Still, lounge access is a definite plus, even on purely domestic US itineraries and so is pre-boarding, since that is no longer a right/privilege afforded to silvers on most airlines.

On the other hand, even *G is worth less than it used to be (many airlines have changed the additional luggage allowance to one extra bag or 20 extra kilos instead of three bags regardless). Only you can say if it's really worth it to you to get status on an airline you rarely fly. I did and I'm enjoying some perks but have not yet decided whether or not I will re-qualify. The "cost" was/is the difference between first and biz on a transatlantic or transpacific reward with LH.