Jon202, the image will be brighter. If that makes it clearer to you then that's fine. The OM 'finder and screen system is IMHO the best, most versatile and well thought out system of it's day, as was the entire OM system. Sorry to use the word system so frequently, but that is just what it was, or should that be, is? The viewfinder is superb anyway but the choice of screen can make a big difference depending on eyesight and chosen subject matter.
BTW, I am, what's now known as a senior citizen. One lazy eye, one reasonably good but I wear specs. all the time. I use 1-4/4n screens in all my bodies, lenses from f1.4 to 5.6 with no problems. Well, to sum up, if I was taking photographs of BC in dark places regularly, I might just prefer an f2.. Ah! No, then I would go for the 85/2, but if it was pics. of groups of people in a nightclub, then the 28/2 might be a better choice, despite the distortion, afterall it's seen on the tele. all the time these days, so it must be OK.
DOF hasn't been mentioned. However, all this is getting away from the original post. The Zuiko f2's are a much more recent introduction than the original f3.5 (which I have and is excellent) and f2.8 versions, regardless of maximum aperture, will therefor be more expensive and beyond my means, but then I don't need them anyway.
pdeeh, here's a possible solution. If you are committed to a maximum aperture of f2, then why not try one of the less costly Vivitar or Kiron (I used to sell those) and see if it meets your needs. It would give you a chance to evaluate before you splash that much cash on a Zuiko.
Oops! I see darinwc has already suggested that, so perhaps it's a not so bad an idea.