Depending on where you live, they're not bad at all. Kind of cheap and cheerful I would say. Their complementary is not too expensive and you get a bit of everything. They're not the best but they're not the most expensive either.
I would say that depending on which complementary he's offering, they are definitely NOT the best for transport (ambulance, helicopter) cover. (Only covering up to a maximum of 5,000.- p.a. with the Global for example). If the rest seems good to you go for it but you might want to think about taking out a Rega insurance to cover this.
http://www.rega.ch/fr/start_fr.aspx
If you're employer is offering to pay 90% of your premium then go for it!