I don't know which Android devices you've used, but I simply haven't found this to be the case. From my experience, the touch response on high Android devices (such as the Galaxy Nexus) is indistinguishable from iOS devices.
If the Galaxy Nexus is really on par with the iPhone (and I'm highly skeptical of that) then I might stick with Android for my next phone, but otherwise I have to go iPhone just based on touch characteristics alone.
EDIT:
http://androidandme.com/2010/03/news/is-multitouch-broken-on...