Looking at the comments GVA is really not that bad - granted it is a zoo on week-ends in the ski season but otherwise it is not too crowded and quite efficient. You can get to France through the Swiss side terminal - just collect your luggage in the main bagage hall go out into the Swiss side and then walk upstairs (to the left I think) through a small door and you are in France! There is a place for someone to check your passport but I have never seen anyone there. The French side is much less crowded and has a full set of (albeit fewer) check in desks so you can check in and leave your luggage here without a long wait but be warned - you need a boarding card to go from France to Switzerland in the terminal so you can't go back to the Swiss side once you have left - make sure you have all your children with you! I have no idea if there is any public transport or taxis on the French side - probably not - but there is a full set of car hire booths (if you hire on the French side you must bring it back to the French side otherwise Herz or whoever will charge you lots of money to move the car about 100m). There are lots of shops selling pricy watches and chocolate and a reasonably good duty free - before security - but the cafes in the departure satellites (after the security has removed your drinks) are horrendously expensive - €3 for a small bottle of water anyone - but aside from that the only problem is the lack of seating downstairs however if you go upstairs near the frequent fliers lounges (follow sign for chapel) the lounges are usually empty.