I just HAD to read chap158 (Kou vs Mishima) to the end.
I found both endings quite different in execution, and like both of them for what they are.
The anime had the benefit of medium, where it got to use transition effects, zoomouts, soundtracks and panning etc. In particular, Aoba's " Kou knew of my pain and happiness all along" speech was greatly accented with use of those flashbacks and soundtrack. This part was done better (or rather, could only be done to that effect) in the anime.
The ending sequences also provided a lot more closure for the other characters, and the story as a "whole", if you consider that a story is made up of all those characters.
The manga ended more abruptedly with Kou and Aoba holding hands, and by leaving us with that, the entire focus was on the pairing, resulting in a much more powerful ending. Also, the lack of soundtracks and panning during Aoba's "Kou knew..." scene meant our sole focus were on her words. That too adds to the impact. This ending wasn't about anyone else but them.
I found the clover speech to be better suited to the manga ending than the anime. Being placed immediately after that scene, much of the notion of the two's relationship is retained, making it more meaningful as well as having the "tying it all up" effect.
In the anime, this "tying it all up" was done partially, if not totally, by the ending sequences, so when the clover speech started, the show was more or less in a finished state, making it seem a bit tacked on, disrupting the flow a bit.