Hi
Here are two other big real estate websites:
http://www.homegate.ch
and
http://www.immostreet.ch
Can't really say I know Plan-Les-Ouates that well but I doubt there are any really "bad neighbourhoods" in Plan-Les-Ouates.
Unfortunately the real estate situation in Geneva is a bit "tense" at the moment (a bit of an understatement that):
Flat rentals in Geneva
I would say your best bets are either to get your company to find something for you, to first stay in some temporary accomodation and to look for something when you get here or to live further out (in the Vaud canton for example) and to commute by train.