well if you look at jeffs episode one he just released you can see how 24fps on two's sort of feels and moves. its smooth but with still a bit of choppyness. which imo still looks lovely. on ones its obviously super smooth. also one twos theres the benefit on animating certain things on ones and others on twos. to make them seem fast. so depends on your desired look and desired way of working.
Shooting on 2s doesn't mean you get choppyness and shooting on 1s doesn't guarantee smooth motion. That all depends 100% on how well spaced your incremental moves are. Timing and spacing are the key to smooth motion. Take a look at Robot Chicken, the recent seasons have been really smooth and it's all shot on 2s. I even believe most of "Hell and Back" was shot on 2s.
I almost always shoot on 2s and might use 1s for a fast motion. On 2s your are just limiting yourself on how much you can break down a movement, so you have to be smarter about your spacing.