Posted By:
Eric BrehmI agree with Scott, SMR is good to get a feel for relative valuation between sets, and among cards within each set. As you have seen, it is often slow to react to apparent changes in the market (e.g. when certain issues or cards get 'hot'). In some cases maybe they just haven't gotten around to updating their prices yet; I have no idea what their methodology is. Nevertheless, SMR is widely used as a baseline for pricing by both buyers and sellers, and is thus a worthwhile reference.
Vintagecardprices.com provides actual sales figures for all the auctions they track, so you can do your own analysis of the data as you wish. You can throw out the unusually high or low sales, average them, try to discern a trend over time, or whatever, in arriving at what you think the 'market value' of something is. Many of their sales figures include links to images of the cards in question, so you can see what the cards that sold actually looked like (e.g. how strong they were for their assigned grade).