Just returned last week from a Swiss First R/T ORD-ZRH-PMI. The Swiss lounge at ORD ( terminal 5 M12) has both a First & Bus. side. It opens at 12:30 PM for the daily flight LX 9 to Zurich leaving at 4:15 PM. Lounge has drinks and nice selection of hors d'oeuvres. Service on both trans. atlantic flights was superb. Champagne this month: Cuvee Charles Gardet Brut 1996. Flight crews were all outstanding.

Based on info. from this board we ( family of four ) used the Swiss First lounge upon arrival in ZRH then purchased a 24 hr.train/trolley pass (8 hr. layover) and spent several hours around Zurich... then back to the Swiss First lounge to wait for our flight to PMI.

Flight to PMI was on a Avro Jumbolino ( 2/3 seats across). After First to Zrh C class was a tight sqeeze as they do not leave a middle seat open on 3 seat side if the flight is full, but the meal was quite good.
Enjoy your trip!