Perhaps I'm in the minority but when I make a "good" character, I do so knowing and accepting that I am foregoing the "quick and easy" route to success. This means I will likely gain experience slower (by virtue of scruples interfering with my mass murdering spree and/or turning down quests that interfere with my character's morals and ethics) and likely gain gear slower because I have to take the long "high" road to get it.
To me, that's part of the fun of playing a "good," character. Overcoming the limitations you've placed on yourself by your moral compass and still managing to accomplish the task is the biggest reward to the play style (in my opinion).
I've never really been bothered by the fact that "evil" characters gain more total experience in a game like this because the challenge of not compromising my character in the process of beating the game has always been more appealing to me than hitting level 21 instead of level 20.
