I'd recommend UA's MP program. While the perks for the M&M card may be better, at UA, you reach Silver after 25K and Gold after 50K miles. Silver gives you free access to Economy Plus (you can also buy it for the first year - I believe that it is $349). Eco+ has 5-6 inches more legroom. I am as tall as you are, and the difference is immense, believe me! When booking at United.com, you can reserve your seat immediately when you have Eco+, including exit and bulkhead rows.

UA Gold gives you access to US's Red Carpet club for international flights, and LH's Senator lounge. You can check in at the 1st class counters. Lounges usually have wireless access. My company has negotiated a deal with OnePass, which lets you log in to all kinds or wireless providers. Very convenient.

And, IMHO, UA FAs are much friendlier than LH FAs.