I have been using 2x6V Rolls Surette deep cycle batteries for the last 4 years. No issues to this point. I'm about 50/50 shore power/boondock.
RollsBefore that, I used a couple of Trojan T105's and replaced them after almost 4 years of 60/40 Boondock/shore power.
Trojan Before that I had a single (cant remember the brand exactly, but well known) Marine deep cycle (they say) which I used for one season only before upgrading to a true deep cycle battery as opposed to more of a starting battery.
Either Rolls or Trojan work well IMO. I used a 1500W inverter with both setups.
I would never go back to a marine "deep cycle", but that's just me................