Has anyone had experience lately with renting a car in France and returning it in another country (ie: Switzerland?) I imagine it would be much cheaper to return it before crossing any borders and renting a new car in each country?
Any advice or suggestions much appreciated.

There usually are heavy cross-border charges. However, if you are flying back from Geneva or Basel, you can return the car in the French section of the airport and not incur those fees. If you plan to tour Switzerland, you might plan it in such a way that Geneva or Basel is your departure point from Europe so that you can return your car on French soil.

Well if you drive it to Switzerland from France, you will have to buy a vignette(unless the car already has one.) I believe that will cost an addition 31.5 Euros on top of everything else that you'll pay.

http://en.wikipedia.org/wiki/Vignette_(road_tax)

Very few people have had that experience because it costs a small fortune to do that. Drop it off in France (or follow Michael's suggestion if applicable).

I will suggest you take pictures of the car before you take possession. Dents and scratches will then be recorded..Don't learn the hard way..