I posted this somewhere else. Dont know if it is of any help:
"Owning both of them and lately having used the 24/1.4 a lot I just re-experiencing the 28cron and I am interested how you think about those 2 lenses (on the M9):
I see it as:
Framing and focusing:
framing with internal finder (in case of the 28mm lens) means focusing and framing with the same finder means more precise focus and framing when shooting wide open (which is one of the reason to own those lenses). When I use the 24mm I have an external finder. When shooting wide open non static subjects I often have to use the internal finder and gues the rest because I need to see the rangefinder. Chnaging forth and back between internal and external finder in case of the 24mm leaves more room for either focus inaccurancy (when looking through external finder) or framing inaccurancy (when using internal finder) shooting wide open. Of course not problem when you sep down and have a little more DOF.
This means 28 has an advantage here IMO.
Subject isolation:
I would see the edge for the one step faster 24mm lens - however with 28mm at f2.0 its possible to. Differnce seems not too big.
Signature:
very subjective...It looks like the 24 draws a boit more "dreamy/creamy" wide open tand the cron a bit more crisp. I am not sure though didnt shoot enough with the 28 on the M9 so far. 28 seems very well balanced - sharp but not clinical
Handling:
28 is lighter and some what smaller than 24
focal length:
I like shooting at small-medium distance with those lenses-and a lot people in my own environment, friends, family, kids etc.
24 seems to give those images a more dynamic interesting look and 28mm seems to give it a more natural look (perspective wise). Of course we cann allways crop 24mm to a 28mm fov. My personal idea when getting the 24lux was this more dynamic look. I wanted to force myself to shoot more spontanious and with more extreme lenses to create "more interesting images" with a certain chracter. (like somemore dynamic wide angle look images and when using a different lens more compressed onces)
Anyways, I am interested how you guys see those 2 lenses and your ideas behind using them."