When I got my wheel I immediately felt buyer's remorse because it was so much more difficult than I had expected. Lap times were generally about 5-6 seconds slower in most cases.
Fast forward 3 weeks, and here I am to tell you that the only way to fully enjoy this game is with a wheel. It does take some practice, but your times will definitely improve as you go along.
Case in point, I just finished golding all 60 license tests yesterday...many of which I couldn't even dream of beating with the controller.