This is a huge topic. The Apple Fanboys and Fangirls will swear the iPad is the "second coming". The vehemently anti-Apple folks will swear that they will never submit to the cult of Apple.
There is no doubt that iPad has an advantage with the sheer number of apps available.
In my humble opinion, the biggest drawback to the iPad is Apple's stubborn refusal to share the playground with Adobe Flash. Actually, it is probably a battle between two playground bullies. Meanwhile, tablets using the Android platform are gaining in popularity.
Most other tablets are less expensive than iPad2.
iPad has the convenience of downloading everything easily via iTunes. But those who hate the dominance of iTunes, are happy to find more options available via the Android platform.
Will the iPad or other tablet replace your laptop or desktop computer?
From Finding uses for the iPad 2: A skeptic gives it another shot: "The iPad2 is smaller and lighter than the original, but it’s still quite large. When held, it’s like holding a hard-cover book, just lighter. A lot of the applications that I use I already used on the iPhone, but the majority of them just look and act better on the iPad. ..... Will it replace my Macbook Air? Not a chance! I need that keyboard and there are too many programs I need that the iPad2 simply won’t provide, or just aren't convenient on a tablet."
'You see, I don't believe that libraries should be drab places where people sit in silence, and that's been the main reason for our policy of employing wild animals as librarians.' (Monty Python)