Smart Chargers and 6-Volt (12 volts DC) Dual Battery Setups - Recommendations & Feedback

I know this one's been beaten up some here on the forum but would like some feedback and recommendations here with the coming of winter and the storing of trailers.  I'm aware of the WFCO discussion and the potential for less than adequate charge rates and declining battery life therein.  I'm wondering how any of you long-term (with the dual 6-volt battery setups) T@B owners are faring with the dual 6-volt setups over time and what your recommendations and suggestions are for others planning to purchase a robust or more than adequate smart battery charger?  I have done some looking around, checked user reviews, etc. but would still appreciate people's experiences and maybe things to look for and that you might change when delving into a smart charger purchase.  With the coming of the dual 6-volt battery setups in the T@B 400 trailers this would also help out others down the road.  

Another underlying concern here with me is that my prior 6-volt setup in my 320 T@B seemed to be fading two years into the install and believe it can be attributed to less than adequate charge rates, etc.  So with that said, I'd appreciate your thoughts and experiences to date (post up some photos too if you have time) if you've had either success over the past 2-3 years with the dual setup and what you'd either do differently or recommend to others, along with suggestions for purchasing the best smart charger on the market within reason.  I would like to be able to basically attach the charger to the battery setup, plug it in to shore power, unplug as needed and hit the road!  

Thanks!