There is simply no comparison. LH is a world-class airline with one of the best first class products in the world. UA's first class is barely comparable with Emirates business class, but UA carries cheaper wines. Both seats are lie-flats, LH is just awesome. See for yourself:

http://www.youtube.com/watch?v=bbAk_Fs8sJs

There is simply no comparison, and I have flown both LH first and UA first.