I should give it a try, I suppose...but it's going to be really weird.
It's been a joy to use. I wrote the first 45k words written on the OS X version on my laptop.
But in May I started a new job, and then used the iPhone version to write the next 50k words. Pretty much written entirely on the London tube to/from work.
I've also emailed Keith, the lead dev, a few times and he's been very friendly. Even incorporated some of my suggestions into updates of the iOS version.
Anyway, if Emacs works for you, then I'd say stick with it, unless you see some compelling reason to change.
For me, I had never written a novel before so did some research and chose Scrivener. Prior to this my longest work was my PhD thesis, in LaTeX.
As a data point, Donald Knuth uses a minimalistic Ubuntu setup with FVWM2 and Emacs (with a lot of custom keybindings), and that's enough for writing his big volumes.