I think his is quite a bit better in multiple aspects, primarily because you retain a full width view of the comment regardless of how many tiers deep you are.
I did think about implementing comments like Reddit / Alien Blue, but I found that it involved too much scrolling up and down and having a button at the bottom reduced that.
My big problem with the tiered implementation is that it only really works until like 4 tiers deep. After that you have a long column of text. I haven't really found a solution for that except a "View replies" that pushes another view controller with that comment at the top tier. Seems clunky though.
I think his is quite a bit better in multiple aspects, primarily because you retain a full width view of the comment regardless of how many tiers deep you are.