While researching a leisure battery for my caravan I came across various articles or views on AGMs not being the "gold standard" compared to EFBs. I had seen that EFBs were fitted to most cars but "upmarket brands", such as BMWs, got AGMs. The thoughts were the development effort put into EFBs meant they were a challenge to the more expensive AGMs and that they were starting to be fitted to the upmarket brands. I am interested in people's views and any real life experience in advance of having to replace my EFB. I did end up buying an AGM for my caravan based on the claim that they are much slower to self discharge.   

This is what VAG say in their Self study guide on batteries:-

 

Basically AGM are the best but heat kills them...so they need to be shielded from the engine heat.