Don't have any 3s. Have several 2s. 3s are supposed to have bigger, more durable bearings. Sounds like a good idea. 2s don't last long between rebuilds on a commuter.
Might not matter much on a low-mileage bike.
If I could go back to before I set up all my bikes with CB, I'd use Time pedals instead. Same mud/snow clearing, far better durability.
At a 2nd thought, I'd say that stainless is more important than if they're 2s or 3s.
Unless you really like to do maintenance. Not that it's particularly overwhelming. But you do need to pull the 2s apart every couple of months and regrease them. And every 2nd/3rd lube job, replace the bearings.