All companies involved with the Superyacht Training Group have to have demonstrated professionalism in their field. Being a member means they quite evidently and regularly promote safety through bulletins and engagement with regulators.
All trainers involved with the training group within their own companies will have many years of experience and knowledge to back-up their syllabus. Usually with a maritime background themselves, they've been there and done it but learnt the most effective means of training.
Bringing on trainers to your vessel will be a significant saving over sending all your crew ashore. Not only that, but by training your crew in situ on the equipment you have on board, the knowledge of the crew will soar dramatically and likely result is less accidents or incidents.