They do some good training. All based on the police "system".
Go do it, learn what they have to offer and move on would be my advice.
There are too many people who consider the I.A.M's training to be the ultimate and never move on to other stuff. They seem to get caught up in some kind of cult menatality.
Quite a blinkered view in my opinion.
Although they call it advanced training it is just the next step up after normal training that you take to pass you test.
I dont want to put them down because the information and training they pass on definitely saves lives and improves roadcraft.
The next rung up the ladder after I.A.M would be R.O.S.P.A. They have 4 different levels (I.A.M is just pass or fail), bronze, silver, gold and assessor.
Bronze is slightly above the level of I.A.M so you can imagine that to attain Gold you've gotta be pretty damn good.
Both organizations offer good training. Dont forget the Police safe rider scheme either.
FYI I run sports rider training over here in Germany and the best way I can describe it is "California Superbike School for the road".
Its very technical and is aimed at high performance road riding with the emphasis on getting the most out of your sport bike on the road.
In short.... Nailing it while maximizing your fun and minimizing the chance of things going tits up!