I'd suggest you pop into an Apple store or, failing that, John Lewis branch and try one out for yourself.
As for security etc. They're the only device that have been approved for use by pilots to keep their flight documents on and are also in use in hospitals all over the US and by several health boards in this country. They are not easy to break into when set up correctly and can be tracked, locked or even wiped remotely if stolen.
They work with both Macs and PCs and can import or export documents, photos or movies to either machine. The iPad cable plugs directly into a USB port to transfer data but can also do so via iCloud wirelessly. The contents of the iPad can be backed up to iCloud wirelessly or to your Mac/PC when synchronising it by cable or to both if you need to be extra safe.
The only software that needs installing on a PC is the latest, PC version of iTunes, a free download from the Apple website. This provides all the connectivity your iPad needs and provides a portal to the files on your computer.
If you're not sure on how to set it up I'd advise getting it from an Apple store as they'll set it up for you and give you some free tuition on how to use it.
Before making the decision though, I'd wait a few days, new mini iPads are due to be officially announced in a day or so and should be quite a bit cheaper but with similar capabilities and a smaller 7" screen.
If you really like the iCloud idea you'll also get a free Apple e-mail address with the cloud so you could be "**** ****@icloud.com"
Bob.