Just a point of clarification:

With UA Mileage Plus Premier Executive and 1K's really earn 200% total program miles flying in paid Y, 225% in paid C and 250% in paid F. (But just 100% Status, or Elite Qualifying Miles in any paid class of service). So on the earning side LH isn't all that far ahead of UA. A balance of paid Y and C probably earns more total program miles with MP.

My favorite "difference":

North America to South Asia in First Class via Europe (LH to Europe/LH or SQ to SIN)

- with UA MP = 120,000 miles
- with LH M&M = 240,000 miles (requires a 3 region award)

* you may able to swing this award for 180,000 miles on LH M&M if you fly via the Pacific although I have no direct experience with this scenario.