Especially if you plan to do an A-class RTW, you might want to check out LH's program and compare it to UA. For A-class travel, LH gives you 300% (both status miles and spendable miles), compared to either 125% or 150% (I forget which) on UA. There are other differences to consider as well (award travel usually requires more miles on LH, SEN status on LH gets you into UA's lounges on both domestic and int'l flights, etc, etc); the better choice depends on what you'll fly to earn status and where you expect to fly and redeem after getting status.