If it's mainly for reading pdf's / arcticles?
i'd recommend iPad2 because it is faster for rendering large PDFs. but if your articles are only 10-20 pages then iPad1 will suffice.
If that's all you need it for, get a used iPad 1 for cheap. The iPad 3 supposedly has a "retina display", which will allow for clearer text, but the regular iPad and iPad 2 have nice sharp displays already.
No, you need iPad 4 for that. iPad 3's pdf engine is horrible and its very slow.
Does the Retina display on the iPad 3 will make a big difference you think?
You haven't heard about the rumors that the iPad 3 will have a retina display?
As others have said, iPad 3 doesn't exist. However, as an owner of iPad 1, I would say that you should get the 2 for one reason only: I love my iPad, but it's heavy. Heavier than I would like. It's very well made, but after a while my hand gets tired holding it when I'm reading books. The 2 isn't feather light, but it feels much lighter to me. So, if it's just occasional use, get the 1. If you're going to be reading for prolonged periods of time, 2. Or wait and the 3 will probably be better, clearer, lighter. Good luck.
No, you need iPad 4 for that. iPad 3's pdf engine is horrible and its very slow.
If that's all you need it for, get a used iPad 1 for cheap. The iPad 3 supposedly has a "retina display"..., but the regular iPad and iPad 2 have nice sharp displays already.
So wait iPad 2 doesn't have retina?
Actually he's wrong, you really need the iPad 5. It'll broadcast PDF files straight to your brain implant.