So glad you asked that question. I've been staring at that one on my elimination list too!

I haven't grown "Harvey Koop", but I see that it's a sport of "Spartacus". If "Spartacus'" genes come through, it will be a great performer and tuber keeper. I found this with "Vassio Meggos", another sport of "Spartacus".

Generally, a newer released variety will command a higher price - especially in the first year. Many of the vendor's haven't updated to their 2012 prices. Hopefully, the price will come down.

I've had a rule the last two year. I go to the dahlia show in September and pick two dahlias that blow me away - and buy them for the next year. Last year, This year - it's Harvey Koop and Vista Lindsey.
Of course I'll be adding more too; but those choices are based solely on my first impression of seeing the bloom at the show. Harvey Koop is unlike any other dahlia I've seen. I'm getting it from Corralitos Gardens. They had a slightly lower price than other sellers.

Good to hear an opinion of someone who has been able to see it in person. Pictures alone were enough to get me hooked!
I did see that Corralitos had a lower price, but I've never ordered cuttings before, just tubers. I know tubers vs. cuttings is a topic for a whole other thread, though :) I'll probably just stick to what I know I won't kill.
Thanks for the feedback on Harvey Koop....hearing you were blown away by it has bolstered my confidence in purchasing it!

Absolutly worth the cost. I just moved so had to leave all my dahlias in the ground as the new owners wanted them. Will rebuy.
Who is on the list for good growers?