VHS's color encoding is pretty crummy. Essentially, what happens is that the NTSC video signal is converted into YUV (which is fine--it's what component video is) but then the U and V are amplitude-modulated onto the Y signal. This means of encoding video wouldn't be bad if it were the only one used (even though U is only modulated at about 2.something megahertz, compared with 3.579545Mhz for NTSC, the phase-independence of the signal would be a major plus) but conversion to and from NTSC is quite lossy.
I forget how Betamax encodes its color, but I recall it's something a bit better. What's particularly interesting, though, is that there's a format called Betacam which was used in many television stations until it was displaced by digital formats. Betacam captures each line of video in YUV format and then records the Y component at double speed and the U and V components each at quadruple speed. The net effect is that not only are the U and V component bandwidths now only limited to (tape_bandwidth/4), but more importantly they no longer have the relative phase lag effects of other video formats.