Under Settings > About Phone > System Updates, you can update your Samsung Galaxy Nexus to the latest Android OS version, currently codename Jelly Bean (4.2.2 or 4.3 depending on the region and Nexus variant). I would suggest updating this over a wifi location, as the files tend to be large.
There's no Samsung Galaxy Nexus 2 model yet.
Sprint did offer the Samsung Galaxy Nexus during its run.
Samsung Galaxy S
Samsung Galaxy Y,Samsung Galaxy Nexus Etc.
I believe not, Samsung has it locked out. However, you can download a vanilla version of Android, which lets you update. (Sorry, can't find the site right now) The Nexus phones, virtually the same thing, can update freely.
IPhone
I would say Nexus is better because it has 4.0 ICS
It is the Samsung Galaxy Nexus it is the most phone that people more about
no
No. it might damage your phone.
Samsung especially Galaxy Nexus
no