After someone stole my D5000 I had a choice between these two cameras, I went for the D90 as it will importantly for me AF with older lenses. Also it is a far nicer camera to use than the D5000 type body, it feels more sturdy and has more direct controls. However you have to ask what do I require my camera to do, so if you think you are going to want to do video then the D5100 is a better camera. For a stills shooter the D90 has advantages and in most normal prints the iq is a wash, having compared similar between the D90 and D7000 though.