I've tried all three and they all seem to work pretty well. What I did was various drawing and scribbling with each, followed by drawing some technical shapes repeatedly and trying to connect and match lines. Also understand I have a cheap plastic screen cover on the 12.2, I'll have to see what I think when I get my glass cover.
The included stylus is nice and I like the tip on it the best, but its way too light. This internal stylus the hovering dot is the most on target (from viewing with my eyes) with where the mark will be on the tablet. It matches very well also if I don't look at the dot and just act like the tablet is paper. Drawing hexes was great, but the lines are very heavy, not much pressure difference here. I would choose this one first, except its too flimsy.
Bamboo feel UK2. Nice weighting to this pen, but I don't like the rough plastic surface, it feels like I'm holding raw wood (yuck), why didn't they make it smooth? The hovering dot seems off with where the tip is, a pixel or two off it seems like, and it changes with the angle I'm holding the pen. I don't like that. However if I don't pay attention to that, and just draw like the tablet is paper, the marks come out right where I want them to and expect them to. That is good. This pen has the best pressure sensitivity, it is easy to make thin or thick lines. This is the one I'm choosing to do most work with right now.
Samsung replacement S-pen with eraser. Too light. This pen has a similar offset as the UK2, but its different somehow, the offset is different between the dot and the pen in a different way. This pen also does work well if I forget about the hovering dot and just draw. I would choose this pen third of the three, but I'm going to try the mod/trick putting it into a G2 and see how that works out.
So overall I don't really like any of these pens, but the UK2 feel works out the best for me I think in terms of overall functionality. The cheap jerks only send two replacement tips with it (one hard, one soft). All the rest had at least 4 if not more replacement tips.