I must say I own:
1 desktop
1 laptop
1 netbook
1 iPad 3
and I'll say for efficiency purposes the iPad has been MVP (after my desktop)
heres my points:
laptop:
Pro: can do more things, well. . . MS Office, Photoshop, Chrome browsing and I can play DOTA2 on it. . .
Con: Battery life, weight
netbook:
Pro: longer battery life (6 hours or so) light weight, MS office, Chrome browsing
Con: cant play DOTA2, I have to wait like 2 minutes to boot up or like 30 secs to wake up, I have to take it out of its case (i know this is a lame point but it counts
iPad:
Pro: longer battery life (8 hours) light weight, Office suite (not MS), Safari browsing, Photoshop, Adobe reader works wonders for many of my classes that I used to print readings (cause I had to highlight, make notes and stuff) now I just read them on the iPad and highlight/note in the iPad itself, I just slide the switch and I can use it instantly,
Con: I cant play DOTA2
now if you compare iPad3 with other tablets:
at least in the software part, many of the tablet apps are giant smartphone apps (the exact same thing but on a bigger screen) the iPad developers developed new stuff on the iPad apps (you can easily see the change on Social apps (facebook/twitter)
I cant really compare much since I've only used an Android tablet once, but that was my impression