Yes, thank you purpleinopp! Since I'm still new I can't post links myself. To add to what I said before, what I really like about the few plants on that site is that it makes it "easy mode" to figure what to plant in CO. Since they've taken the time to test and vet these plants, they should have a good chance of working and it's a nice, small list for beginners to start with.
On the other hand, I'm not completely blind to the fact that they partner with other growers who have influence on which plants get priority for testing through the program. I suppose that I should also note that the plants on the list aren't bulletproof as I have had no luck with Kniphofia yet. Tried a well established Kniphofia caulescens that didn't take.
Of course there are plenty of other wonderful plants out there and plenty of those will work in CO. Still, we designed our initial landscaping plan for our new home around the Plant Select program and have about 95% of our plants from that list.