LH First Class is far and above better than either UA Polaris (True Polaris or Fauxlaris). From customer service to on board amentities, food & drink, not to mention the First Class Lounge in Germany makes it a NO brainer.

It's a truly remarkable experience, while UA is simply "standard biz" class.

HOWEVER, if you're talking business class, as much as perhaps the soft product (food/drink) may be slightly better on LH, UA with True Polaris (for seat and privacy) would be my pick. If Fauxlaris, (2-2-2) then go with LH.