Well Edward I must admit I have been impressed with these chargers because they do turn round battery charging times if you stick to the correct routine, and that is you run the battery down till the lift lockout cuts in or the battery is down to thirty percent charge, you then put the truck on charge when the battery starts gassing the air pump starts blowing cool air into the cells agitating the electrolyte which then reaches its S.G. Quicker but at the same time the electrolyte has not heated up as much, therefore dose not need as long to cool down.
This type of charger won't start charging a battery unless there discharged to at least 30% so stopping opertune charging ie putting the truck on charge during tea and meal breaks as you know that can shorten a batteries life cycle. This means that battery life expection of say 4/5 years is acheieveable in high volume business's.
Battery hygiene I've noticed if you keep the tops of the batteries clean you get less cell failures
This type of charging also means less topping up is necessary due to less gassing ie due to quicker charging.
I'm sure that one company I know of still has the original batteries in his trucks and there coming up to 7 years old.

Regards Titus