On the one hand, I wish I'd known more before buying my 2009 with the 3.33GHz quad CPU, Apple RAID card and four HDDs installed, since in hindsight, that wasn't the best value. I was Mac-stupid, and believed that one could not swap CPUs and such, and didn't realize the markup Apple charged for their custom options.
On the other hand, I did unpack and jump right into editing a feature-length movie with absolutely no hassle whatsoever. Eventually, I learned a great deal about modern Apple devices, and have modified all but my 60GB iPod Photo (which I may attempt to modify someday, haha!)
All the while, I'm interested to see what the future brings.