Performance of the iPad 3 is solid and, happily the advent ofiOS 7 hasn’t caused the dreaded slowdown on the iPad 3, it still runs well. If there’s a couple of areas the iPad 3 suffers it’s battery life and value for money. Battery life is reasonable solid but not outstanding. You’ll get a full day’s use out of it but if you’re using 3g that will reduce significantly.
It also takes a fair bit of time to recharge meaning you won’t be able to blast it for half an hour before you leave the house. A couple of other things to consider if you’re looking to buy and iPad 3 second hand is that it uses the old style 21 pin Apple connector as opposed to the new Lightning one. That means that if you have an iPhone 5S, 5C or 5 you’ll have to use different chargers.