If you dont mind paying $3000 vs $1500 take Swiss.

1.It is a non stop flight (from the west coast)
2. Nicer cabin

If you decide to take the $1500 UA fare use miles to upgrade if you can. The IAD-ZRH flights are full most of the time and a Mr. Chicken upgrade might not always be an option.

You might also want to check award availabilty on LH.

Ben