Why does my quality feels off?

I own an old D5200 that I haven't used in a while. I recently bought a D90 and have been taking quite a lot of pictures with it.

Is it just more, or does anybody else think that the quality on the D90 looks better than the D5200? I think this is weird because the D5200 is much newer and has a better sensor, but whenever I take a photo with it, it ends up low quality. Has anybody else experienced this? Thanks.