Spectrum is one of those sets that the majority of people that I've read simply do not like. I'm not really sure why its is so unpopular, because I don't know what any of the cards look like other than the Granderson's. The nice thing is, given that people tend not to think twice about Spectrum, I've been able to pick up a nice grouping of cards on the cheap. Much like UD Heroes, Spectrum provides the opportunity to put together the "rainbow" of parallels, except this time with shiny, reflective goodness as well.
The main Granderson in the set is part of the "Spectrum Swatches" series, that looks like this:
Granderson with a glove (finally!), shinyness, gray swatch, you get the idea. These cards have a number of parallel versions. There is the main version (teal? turquoise?) numbered to 99. In addition you have:
Brown Auto (#/30)
Lt. Blue (#/15)
Green Patch (#/15)
Lt. Gray (#/5)
Dark Gray (1/1)
Even in slightly incomplete form these look pretty sharp together, don't you think? (I couldn't fit the light blue #/15 in the shot, but it looks basically the same as the first card #/99. Oh well.)
Other than that slew of multi-colored game used parallels, there is one other card in the set--a Dual Spectrum Swatches card with Magglio Ordonez #/99. I have no idea what this looks like and don't really want to know. I know that sounds spiteful, but a lot of people spent a lot of time hating on Spectrum and based on the one card (and its variations) that I have/have seen, I don't mind it at all. I'm sure things would be different if I were exposed to the whole set, which is why I'm apprehensive about finding that Ordonez/Granderson card.
Anyway, that's my two cents on Spectrum. For the sake of other collectors out there I hope that they improve their set in 2009, but for my sake, just give me some nice looking Granderson cards and I'll be fine.