I wouldn't say it's the loudest part of the Etihad. It's not louder than SSL1 when that gets going, and in comparison.Although 115 is next to the away fans you can't see them like we can in 109/110/111. And because we can see them we have banter with them. Yesterday we sang "you're just a shit Danny Dyer". Followed by "you're just a fat Danny Dyer", and "You're just a bald Danny Dyer to a bemused West Ham fan.
Many sections in the stadium would have barely heard us or not heard us at all but being next to the away fans generates atmosphere, and unlike @Gone for a Burton wanting away fans where we are I disagree. Kippax corner is often the loudest part of the stadium and that's largely due to being next to the away fans.
As you say
I used to stand in 110, so I know about the banter. 111, 110 and 109 over look the away fans at an angle, so there is always plenty of eye contact and verbals between both sets of fans. Lol! Whilst SSL1 is side on to the away fans, so that eye contact and interaction between the 2 sets of fans isn't there as much.
111, 110 and 109 isn't as vocal as it used to be. But it is improving again. It always turns up for the big matches. There isn't much singing and support from there for the lesser matches. 111, 110 and 109 is more if a reactionary singing section to the away fans, rather than constant and out and out singing and support. That isn't a pop at the fans in those blocks. I absolutely loved my time in 110. And I miss it like hell when it was like it was against West Ham on Saturday. :-)