The reviews are very positive but even putting my personal feelings aside about voice recognition, I don't understand why Google is focusing on this as a key selling feature ... largely because typing texts and emails is relatively private and non intrusive.
Personally, I am not worried about Google's ability to support a 'phone.' Why? Because 1) Google doesn't make the phone, it was outsourced to a company that makes mobile phone's for a living and 2) the Google phone will be supported by the carrier (T-Mobile, Verizon, AT&T, etc) no different than any other phone offered by a carrier.
One noted downfall of the Nexus One is that while it does seamlessly integrate with the the web, social media, email, calendar, search and contacts functions, it lacks the music / video integration of the iPhone. This is a big issue that everyone (but Apple) faces today so companies continue to integrate around this with faster processors, better cameras, better rate plans, etc.
So, is the Nexus One an, 'iPhone' killer? Probably not but as cool as the iPhone still is, not everyone wants to be tied to Apple. So, music and video my be sticky for existing iPhone users (who wont be switching anyway) but it might not be the killer app for the rest of the phone using universe who will ultimately upgrade to a smart phone.
Here are a few personal observations:
1) The new super phones like the Droid and Nexus One will make Apple innovate faster. I would expect to see a better camera (w/ Flash) on the iPhone in the next upgrade. Others are speculating that there will be a new design as well as a scaled down iPhone version.
2) Is the iPhone's killer app the ipod's music and video? If you recall, it was when it first came out. However, I think the real killer app is actually the 'iTunes Store' which allows us all to download apps that truly personalize the phone and make it an integral part of out lives. Contrast this to the Droid, where there is much more devise personalization (like a PC) but requires a much more sophisticated user.
3) Apple's exclusive deal with AT&T was a winner but I think the Motorola's Droid and Nexus One need to hit multiple carriers FAST to gain traction. Verizon has a good base of subscribers for the Droid but I don't think it's compelling enough to actually get people to switch carriers like the iPhone did. Also, T-Mobile's subscriber base is too small and too value oriented to make the Nexus One a mass market device.
4) If I was Nokia or Samsung or any other manufacturer, I would be worried. In a few years (2 - 3), there will be more 'smartphones' than that 'dumbphones' and these companies (Note: Nokia sells more dumb phones that anyone else on the Planet) and these companies are clearly falling behind.
5) We are entering the 'mobile decade' and Google clearly wants to be a dominant player. Unlike other areas they dabble in, they are clearly making a major mobile play.
6) Google sells roughly $20 b in advertising each year, most of which is tied to Internet searches. As more and more this moves to mobile searches, its not out of the question that Google could heavily subsidize the expensive data plans that currently keep so many people off smartphones.