As a retired S61 jock, with Falklands experience, I am inclined to agree with Ships Cat. The machine works well but does have its foibles. Don't forget that BIH have the distinct advantage of being on site in the sunny South Atlantic, which may account in some small way for them being cheaper than any other operator.
I believe that the distances involved are around the 120 nm mark, so the advantages of more sophisticated machines are nullified to a certain extent. Additionally, with Argentina rattling sabres again, what are the diversion options???