It really depends on the quality of the management. They have to believe that SMS is a key component of the business. It also needs to have a genuine Safety Department (even if it's just one person initially) that has the respect of the crew and the management.
Without that it's all just lip service to appease the regulator. And the regulator must still remain involved and engaged. The implementation in Canada has ironically been quite a failure for the non Part 121 crowd. They essentially used it to help deal with a significant manpower shortage in Transport Canada and really dropped the ball so to speak.
I'm a little bit out of touch with the implementation of SMS in New Zealand and Australia. How far down the ranks has it stretched? Do operators like Sun Air, Helipro, Sling Air etc run full-blown SMS?