There is no REQUIREMENT for differences training under JAR as this only applies to CS prop, tailwheel, pressurised & retractable.
The AA5 series are very pleasant to fly but they used to have the worst landing accident record - possibly because they are a little less draggy than some other trainers, need a bit more runway and have a springy nose leg.
For an experienced pilot who has flown a number of types the handling differences will be insignificant and a checkout with a competent owner should be enough. For a newly qualified pilot a checkout with an instructor would be advisable.