If you want to know if having done the training in Bristow Academy is useful, just look at the number of HAI/BA graduates now working in Nigeria either for Pan African or Bristow, quite a few who have now also gotten into training jobs with those companies in Nigeria.
As a number of other posters have said, the big advantages of BA are the contacts you make while there (and then the growing network of contacts that will lead to over the years) and the quality of the groundschool, particularly the EASA ground school.
In many Bristow operations, even if you apply years down the road after the initial training, "Bristow Trained" on your CV undoubtedly helps when it comes to being considered for a job. A number of Bristow trained pilots who left are also now in senior positions in other companies, both rotary wing and fixed wing.