At the risk of being laughed at ....
Whats the difference?
Only Apple make the IPad. They run an operating system called iOS, have their own app store for applications. The advantage of going Apple is things are generally simpler (arguably), but you pay a lot more for the brand.
The main rival to the iPad are Android operating system based tablets. You'll find hundreds of makes at prices from £50-£350. There is a fragmented market, some tablets are stuck on an old version of Android, which may not run the latest applications. But sometimes the very latest Android applications don't run on the brand new version of Android. Due to the popularity of Android this is happening less and less.
NB: You can not use Apple applications on an Adroid device, and vice versa. Almost all major "non Apple" apps are available to both platforms.
Personally the iPAD offers nothing to me that an Android device can't do. And the **NEW MODEL** Nexus 7 is a good bet if the screen is big enough. though the old Nexus 7 might become cheaper when the new model is out. You are looking at around £200 or a bit less for a Nexus (depending on model), quite a bit more for an iPad.
I guess you need to ask yourself a few questions about what you need the device to do, then post back. eg.
- 3G cpability or just wifi
- Will you use it to take pictures
- Are there specific things you want to do with it/applications you want to run on it
etc/...
