An Ipad can automatically run any app that the Iphone can. Though some look small, you can super size them by doubling the pixles, but some distort a little. Lots of people that produced apps for the Iphone are now making bigger and better ones for the Ipad. Take "Good Reader" For example. The one for the Iphone got you the base app and you paid extra for all the bells and whistles.
My Ipad version. .99cents, and you get all the bells and whistles included.
Some PDFs are searchable, some aren't. Depends on the quality and type of PDF. Alot of RPG PDFs are not actually typed in. They're basicly photocopies scanned in together in a row. Those ones aren't searchable. But many are. I've got over 500 (( Still uploading them as we speak)) So... yeah.
As for 'Why do I want an Ipad?"
That's easy.
It's WiFi.. Most places that you'd want to access a computer you can access Wifi. So you can get any internet thing you can on your computer on the Ipad (( except flash. Apple hates flash)) I went to the bathroom this morning. Sat down. Checked my Email with one click. Updated my netflix cue with another few taps, read the USA today news paper, then read some in SR4A, all in the bathroom on the throne. While listening to my music on the built in Ipod. Had I wanted I could have watched Star Trek in HD.
My PDF library goes with me now. Over 500 Rpg books in a pad the size of a magazine or one half inch supplement.
You can get maps. Directions. Check movie times, buy movie tickes, buy porn, buy pizza. all on the fly anywhere there's a wifi signal. If you don't wanna trust wifi, you can get a 3G version in a month.
All on a computer the size of a magazine.
Keyboard is built in. It's not 'SUPER AMAZING OUTSTANDING' but it's better than keyboards on a phone. I even read threads on this website on her last night just fine.
You can also use it as a 'normal' Ebook reader, but better than kindel. As it's full color and backlit. You can read in the dark if you want to and have full color books. (( It comes with Winnie The poo. lol))
So.. you get
1) Web access to everything except Flash applications
2) Youtube, even in hi def
3) High def movie player
4) IPod built in
5) Any of the thousands of apps for Iphone run on Ipad. And there are lots of Ipad specific ones made now and more coming every day
6) Full color Ebook reader
7) Email

PDF reader (( for a buck. You can get free ones but the freeone I got sucks. I suggest the one dollar one)) That can read your RPG books (( and if you get the 64 gig like me. you can carry 100s of them with you))
And all of it is in hand. WHich puts you a bit more intimate with what you're doing than at a computer.