My iPad 3rd Gen, has been my main computer for 2 and a half years, and I am the General Manager for a family business with 14 people.
I switched from a windows based laptop to iPad and never looked back, no more paid for updates for the operating system, no more lagy anti-virus, no more long boot up delays etc.
The iPad is so simple but yet so complex if you learn the programs. I was forever finding I was loosing track of documents in the sea of folders and programs on my laptop. I was also never completely sure I didn't have viruses on the laptop even when the anti-virus seemed clean because often I would pick up strange malware or warnings in the scans.
Also the way iPad presents all your information and apps when you log in, in the morning, seems so much more manageable than with a laptop. With my lap top everything was presented to me all at once and the fact that you could change so much about the operating system, programs, files, locations, code etc, meant without realizing what you have done, in no time at all, you can have a real mess on your hands. iPad sorted out all that for me, giving me a clean, organized, safe and easy to use operating system and environment to work in.
In a nut shell I am more productive than I ever was before now that I am using an iPad as my main computer! Sure some enterprise programs or software simply hasn't been designed to run on ipad, and sure some software is easier to use with a curser, but I will tell you this, if you can avoid using those types of programs you will be a happy as can be.
When people talk of hitting a wall with some tasks or programs on iPad, I don't understand them, I know with iPad and the App Store there is always a way. Also people talk of not having a robust filing system?!? DropBox, Google Drive, Box, Sky Drive are fantastic and I ave found my information on these storage options are more organised and safer than ever before!
And now with the iPad Air 2 (which I am currently waiting for deliver on) the power out of the Air 2 is insane, Geekbench shows multi-core scores from the iPad Air 2 that beat or are equivalent to many mid 2014 Macbook Airs!
http://browser.primatelabs.com/geekbench3/search?utf8=✓&q=2014+MacBook+Air
Just look at Apples Business Profiles videos on iPad to see how company's are really using iPads, and you will see how impressive and capable these computers really are!
http://www.apple.com/ipad/business/profiles/