I'm not sure we're talking about the same things when you say "faster." Obviously, a Nexus One has a much faster CPU than the original iPhone, and will perform much better on benchmarks (graphics, JavaScript, etc.). However, I've used a Nexus One fairly extensively (as well as even more powerful Android phones like the Galaxy S II), and I think it's completely reasonable to say that the basic UI elements are more consistently smooth and responsive on the original iPhone. Granted, it's been one year since I had hands on an original iPhone, so perhaps I should amend the comparison to the iPhone 3GS.
I'll also concede that in the strictest sense, Android phones are usable: I do have the ability to use them, and many people do use them. Of course, I would also call IE6 unusable, even though it's also clearly usuable in the strictest sense.
I use the term "usable" to describe any product that I would use if someone gave it to me for free and I wasn't allowed to sell it. If you gave me the current best Android phone for free, I guarantee you I would not use it.
My 3GS is struggling with iOS 4.2.1: seconds of nonresponse in certain situations. I'm planning on jailbreaking and rolling the OS back sometime soon if I can figure out how to do it.
I'll also concede that in the strictest sense, Android phones are usable: I do have the ability to use them, and many people do use them. Of course, I would also call IE6 unusable, even though it's also clearly usuable in the strictest sense.
I use the term "usable" to describe any product that I would use if someone gave it to me for free and I wasn't allowed to sell it. If you gave me the current best Android phone for free, I guarantee you I would not use it.