Not sure what you mean about round towers.
The second one is definitely better... that's the point.
I just can't decide if I like the side with solid stone or the side with the mix cobble... the left side ties together better but the right side is more interesting. I just need a good way to tie the cobble in better maybe. When I add stone-knit-corner blocks maybe I'll revisit.
As far as strength, the very tips are bound to be weaker but overall, presuming those are solid stone chunks, I think it could be more resilient than regular squared off crenelations on the bottom. Glancing blows are less likely to take a corner off.
The Dragon Age version had square fronts at the top. I took a screen grab while I was playing. Maybe I'll post it for reference some time.