I've been with Zimex for three years now as Twotter captain. What has already been said in this thread is pretty much correct. Again, the biggest issue being the 5/5 schedule in theory doesn't work out in practice. Extensions of trips and training on your time off are normal ops. The toughest part (for me at least) is being isolated in the desert for 5+ weeks at a time away from friends and family. Flying can get quite repetitious too and not very challenging.
Other than that not too much to complain about. If you are looking to fly PC-6, DHC-6 or B1900 I can't come up with a better employer.
They are still hiring (last I heard) and if you got the JAR license go for it. They even take non typed guys if they sign a 2 year (I think) contract.
Good luck,
FT