From what optima says:
13. What does deep cycle mean?
Deep cycle means using the battery in an application that will typically discharge 60% to 70% or more of the batter y capacity. An automotive battery is an SLI (starting, lighting, ignition) battery. It's plates are designed to deliver maximum power for a short duration. Starting a car typically discharges an SLI battery only 1% to 3%. When an SLI battery is used in a deep cycle application, or in a vehicle with heavy accessory loads, the battery life will be shortened proportionally to how deeply it is cycled on a regular basis.
14. When should I consider a deep cycle?
Any time you need the battery to supply all the operating power for a vehicle or other device. Additionally, deep cycle batteries should be used in vehicles that have heavy accessory loads where the alternator cannot maintain the battery in a fully charged condition.
It sounds like a deep cycle would perform better on a 4x4 and heavy winching. Because of the draw. But if warn says the motor is like a starter then that isn't the case.
How about the deal if i want to run dual batteries that they have to be the same type and age?