It all depends
You have to ask yourself some questions.
1. How much technical assistance do you expect to need?
Your ipad comes with 90 days of complimentary phone-in technical support, to help you with setup, using apple software, backup/restore, just about anything. AC and AC+ extends that to 2 years. If you are technically self-sufficient or have a family member that can help you, then this isn't much benefit. But if you expect to need help using / configuring the device it can be a big reason to buy AC. Without AC, support calls to Apple are charged at the per-incident rate, which for iPad is $29 (£25) each.
2. How reliable is the iPad hardware?
Your ipad comes with 1 year of warranty against manufacturing defects, including battery failure. AC and AC+ extends that to 2 years. They are pretty darned reliable. Personally, I haven't heard many stories about iPads failing in their second year of life so I don't consider this to be a big benefit, but YMMV.
3. How careful are you with your electronic devices?
The standard warranty does not cover accidental damage, nor does plain AC. But AC+ (if available in your country) does. If you break your iPad (i.e., drop it, step on it, or spill liquid on it), you will have to pay for a replacement. Without AC+, replacement with a remanufactured unit is US$299. With AC+, replacement with a remanufactured unit is US$49 (you can do this twice over the two-year period). If you tend to be careless with your devices, or have other household members that are careless, then the accidental damage coverage could make AC+ a good gamble.
NOTE THAT AC+ IS NOT AVAILABLE IN ALL COUNTRIES, SO YOU MAY NOT BE ABLE TO GET AC+ AND ACCIDENTAL DAMAGE COVERAGE IT PROVIDES WHERE YOU LIVE.
4. Do you expect to sell the Ipad within 2 years?
AC and AC+ follows the device to its new owner, and that can increase resale value. Buyers feel safer knowing that
if there a problem with the device (like a bad battery or intermittent button), Apple will replace it under the 2-year warranty as long as there are no signs of physical damage or liquid contact.
Note that AC (or AC+) does NOT cover loss or theft, so don't consider that as a possible benefit. And also remember that the accidental damage clause in AC+ does NOT cover "normal wear and tear", like scratches and dents (as long as it still functions normally).
In the end, know that manufacturers sell extended warranties because it is profitable for them. Intrinsically that means that MOST people who pay for warranty coverage get less monitary benefit from the warranty than they paid for it. But there will be SOME (like someone who breaks their iPad screen a month after purchase, or needs a lot of technical assistance, or has the rare battery failure between 12 and 24 months) who will profit from the purchase.
