Share 'AGM or Standard Battery?'

We think we are going to have to buy new batteries and have been researching what to get.  The problem we have is that the batteries are under the bunks and so it is undesirable to have them gassing, but I am not sure how much of a problem it actually is. From what I have read only AGM batteries dont gas, but they are significantly more expensive than standard batteries. Is there any significant…