Training at the end of the day IS "experience" and could never be considered a negative thing - no one will ever suffer from training from a qualified instructor.
However only an instructor could possibly say that training from an instructor is the only way to gain good experience. (I wonder why they would think that - there opinion should be stricken from the record as being biased
In my mind learning from as many different people as possible is always going to be the best option. Any individual instructor is only as good as the sum of his own experiences and There is always going to be "Good" instructors and "Bad" instructors. I would choose an experienced instructor over a newly qualified one any day for any training I would pay for.
Seeing that going on 5 or 10 different PB2 courses is a very expensive way to learn from the knowledge of multiple instructors. I would suggest that interacting with as many people who own boats (and not just RIBs) all sorts of boats from a kayaks to a battle ships will teach you more than any course delivered from a single individual.
Please don't get me wrong - I'm not suggesting to anybody that they don't take a course - I took my PB2 years ago whilst working for an adventure holiday centre - I am planning to do my advanced this winter when i get my new boat. All I am saying is that training is NOT the be all and end all route to becoming "experienced" and "knowledgeable"
The training courses that really work the best are the ones that run for extended periods of time and have input from multiple people - but at the end of the day - these type of courses are simply "Structured Experience"