Comcast not so comcastic?

So, I have had comcast internets for a while. pretty fast and fairly reliable.

they recently jacked up the price and then offered me cable TV service. I live within range of TV towers and get TV off the air. The signal is high def and looks very good.
I took their offer (it brought my bill back down to what it was).

So, anyways, they sent me a set top box, I plugged it in and - low def.

Looked awful. the box they sent was not HD. Went back to comcast and they gave me an HD box for $10 more per month. A bit of a bait and switch...

Plugged the HD box in and - hmmm. Signal looks better but it is not as good as over the air HD.

Seems like Comcast uses a bit too much compression in their cable service. Details in skin are lacking, blockiness in black backgrounds, and overall lack of fine detail.
Looks a bit worse than Netflix.

Is this experience matched by others here?

I am used to a decent image on my 50" TV. If I can't tweak the signal and get an as good image as I got with my over the air antenna I am going to have to drop the service.

I don't really care that much about the bazillion stations I now get, especially of they all look like sh1t.