I had never worn sunnies for anything, but bought some Oakley's 2 years ago and it took me a while to get used to the,
I got some Oakley radar's with g26 lens, which are a contrast lenses (they highlight red/orange and dampen green). I initially didn't really like them and tried to sell them. When that fell through I decided to give them another go and I'm glad I did as I got over that initial period and I love them now.
Depends on the lenses too. Contrast lens change your perception of things slightly (what I found), so they would take a bit longer than a standard lens.