Yeah it's perplexing. The 50D may be as noisy as the 7D, but it lacks the waxy AA filter that just smears details on the 7D.
LOL! Google "Comparometer." Pick the 50D and 7D. Click the ISO 100 test scene with the fabric and the bottles, etc. Pay careful attention to which one looks "waxy."
In fairness this is about the JPEG engines. The 7D has the better JPEG engine, and both cameras are capable of higher IQ in ACR. But it's the 50D that was "waxy" in JPEG. The AA filter isn't an issue with either body.
It's the combination of inconsistent focus (burst mode in AI Servo and/or AF single point even on static subjects),
If you experienced poor AF you should have returned the body for repair work/calibration.
It's digital. You decide the colors.