Two issues that cropped up during the Nexus One's debut were issues with the phone's 3G signal and the touchscreen inconsistently functioning. Software updates fixed both issues.
The best online retailers to buy a galaxy nexus would be www.amazon.com Cell Phones & Accessories Unlocked Phones,www.bestbuy.com Mobile Phones All Mobile Phones with Plans, or bestbuy.com.
Nexus phones use Android OS. Unlike most Android phones, the Nexus line are considered "pure Google" phones as the OS does not have either manufacturer and/or carrier modifications (in the form of "skins" and proprietary apps). They also typically receive software updates ahead of carrier phones.
Since the question doesn't specify what Nexus the person is comparing it to the Nexus S, here's the order of Nexus phones (and by manufacturer) to date: -HTC Nexus One -Samsung Nexus S -Samsung Galaxy Nexus -LG Nexus 4 -LG Nexus 5
iphone, nexus 1.
Galaxy Nexus
The Nexus S is no longer manufactured. The newest Nexus phones can be bought and used on the Sprint network.
The Nexus S 4G is a CDMA phone and the Nexus S is a GSM Phone. This is the basic difference between these two phones. Most of the remaining configurations are same.
The two issues the Nexus One had on release were the touchscreen not functioning properly, and 3G connectivity. The OS updates reportedly fixed both issues.
The Nexus Series is a good Low-End Smartphone for its money. It seems, although they have a lot of manufacturing issues because of the way they were produced. To get more value for your money, The Newer, iPhone Series, is worth trying out.
The current and most advanced version of the Android Operating system (2.3.4) can be found on the Nexus class of phones, most notably the Nexus S and Nexus 1. However, all devices which run a hacked custom firmware called Cyanogen Mod also run 2.3.4. As of now, no phones still run 2.3.3 because of inherent security concerns and most 2.2.1 devices will just skip it and move directly to 2.3.4+ depending on the time of update. Edit: As of June 2013, the latest version of Android is 4.2.2 (Jellybean). Except for the Nexus One (due to hardware limitations), the rest of the Nexus phones can upgrade to Jellybean.
Yes, most phones these days come with a web cam. The Nexus S has a Front-facing: VGA (640x480)
Samsung Galaxy Y,Samsung Galaxy Nexus Etc.