How good was broadcast NTSC/PAL in practice?

[pidade]

It's tough to say, since all the old analog recordings we have are degraded and, if not, weren't up to broadcast-spec anyway, so there's really no good reference for how live TV actually looked.

There's a lot of discussion already about hue errors, but in terms of resolution, was video bandwidth generally 4.2MHz (NTSC) at the receiver? What was the typical SNR of a broadcast signal?