I want one of these phones
The Nexus One is superior to the iPhone in virtually every way. Multitasking, weight, dimensions, screen, openess, standards support, browsing, expandibility, removable battery etc. It even comes in a sim free version so you're not even tied to one network.
The only reason I would favour an iPhone over it is if I had a large collection of content purchased from iTMS, otherwise I see it as a inferior choice.
I do think it has what could charitably be called a "soft start" but then I don't think Google sunk anywhere near the amount of money in promoting it so perhaps its not surprising. Is it a flop? I still want one, and it annoys me that Google should shut out international customers from buying one because I would like a shot if I could.
I feel most sorry for the Palm Pre. I think that also has a great OS, but I simply don't see a long term future for the platform. It wouldn't worry so much if I weren't a developer and just needed a phone, but I am and I see a lot more potential in android.