Have you become spoiled by the short security lines and easier security process provided by TSA pre-check?
I recently flew IAD-AMS on KLM and was annoyed by the fact that I could not use the TSA pre-check line. Not many international airlines provide TSA pre-check, but Lufthansa now does!
This is one more perk added to Lufthansa, they already have a great fleet servicing the USA and offer great connections to many places in Europe and beyond.
REMEMBER you can use your United miles to book award flights with Lufthansa!