i used work for an outfit that used to fly 500 D's and the 530 doing production external load work. never flew the 600, although we had one at the time and after i left, the 600 shed its tailboom killing the pilot. while i was there, we did have problems on both the 500 and 530 with m/r blades cracking and before my sentence began with the same company, they had a blade part company with the machine injuring the pilot pretty badly. he was lucky at that. one might think that the a/c were abused but that was not the case.
most of my work now (the same type of work, mind you) is done the the as350 and to a lesser extent the 407. if you ask me, the 350 is by far superior to the other types mentioned. it is powerful, comfortable, has a good heat/demisting system, just as quick as the others with a line on, and very robust.
i have no experience with a fenestron, but i can tell you that the 350 tail rotor authority is easily sufficient.
like VP, i too have a lot of faith in the 350 series.
fp