Eh, I haven't found it to be a major problem. I speak fluent oral Greek (learned it when I was a kid to talk to my grandparents/cousins), and can read some Greek, but nobody really expects me to be able to read formal Greek. It's slightly diglossic in that formal Greek is substantially different than the spoken language, partly a relic of the days when it was an actually different language: http://en.wikipedia.org/wiki/Katharevousa