The biggest question would be, are you familiar, experienced, trained, and practiced enough with a single action revolver to be able to realistically use it close, fast, one-handed if necessary, if you intend this to fill a defensive role of some sort.
The procedure for firing all six rounds at an attacking animal or bad guy is pretty straight-forward with the [double-action]. (Actually, it doesn't get ANY easier!) As is the process for emptying the spent cases and loading six more.
With the [single-action] you're going to want to have practiced A LOT to ensure that you can run that gun in the manner, and under the circumstances, that you might need to if "trouble" finds you.
If you are a SASS (Cowboy Action) shooter, you may be faster with the [single-action]. Otherwise that's not likely.