I wouldn’t discount these guys out of hand.
These Global Insights reports have been pretty spot-on, at least for the last 6 years that I have been reading them. I am not saying that you should go buy a house because of their report, but before you go attacking the messenger, you should at least consider their analysis.
Up through 2001 they had LA county as slightly undervalued, which I found hard to believe at the time, but it seems right in retrospect.
By 2003 LA county was considered overvalued, and by 2004 it was grossly overvalued (>36%).
They state up front that their over/under valuations are not predictions of future housing prices, but consider overvalued areas to have positive price pressure, and vice-versa. Given the rapid housing price drop, their models might be overcompensating–they are based on several decades of inputs. A rapid disruption is likely to cause short-term ringing.
Also, in the description of their analysis (at least back when I last read it in detail in ~2003) they do not predict future economics either, rather they look at how current prices compare with current economic conditions–but they do take into account historic economic relationships since price to rent ratios are very different from region to region, as is mortgage-to-income.

It it likely that SD will get an “undervalued” rating on this report sometime in the next couple years.

Anyway, I would take this as one more data point, but I think accusing them of being biased a bit unfair, given that they had most metro areas rated as overvalued for much if the last couple years.