I found that RoSPA dealt with questions about road signs and doing POWDDER checks before i started on the road, whereas the DIAmond test just dealt with machine checks and an eyesight test- similar to the standard motorcycle test- and the IAM dealt with neither- whereas the IAM was the only one to have six to eight weeks or classroom theory sessions as well as observed runs and feedback. (I'm sure RoSPA and DIAmond offer this facility too, I just opted to go for those tests after the IAM test).
There were no slow moving exercises during my RoSPA or IAM tests but there was for the DIAmond test -in a carpark- figure eights, slow riding under control, as well as U-turns in the road, moving off at an angle behind a parked car, etc. (again, I'm sure differing IAM and RoSPA regions do expect candidates to perform these manoeuvres, I didn't though).
Filtering was encouraged during the DIAmond test and if you didn't, you'd fail, but not so much so in the other two- 'make progress', yes, but filtering up to the front of a queue in traffic at a red light for example was frowned upon in regard to IAM and RoSPA I found.
Both IAM and RoSPA dealt with dual carriageway and A-roads, so did the DIAmond test: yet only the DIAmond test involved motorway riding (because of the location in Dublin) although I know IAM and RoSPA do test motorway riding and all three covered rural riding with RoSPA placing most emphasis on it I found, then IAM second and DIAmond third (strictly based on time spent on those road types)
All three placed emphasis on using a system and using it consistently- be it the system of motorcycle control or that laid down by the DSA and all three were done in varying weather conditions by the way. The DIAmond test was done in beautiful weather, the IAM was overcast and the RoSPA test..well I was soaked to the t-shirt and socks even before I met the examiner..
(All three claim to be the 'best' obviously!)
I was glad to learn more regardless of the 'style' and if I can 'cherry-pick' the best from each then it's all good information because any post test training with a decent instructor is worthwhile I believe. £125 well spent IMHO- much better than buying say, an aftermarket exhaust..the best modification you can to to a bike is improve the skills of it's rider through training
