i started out with a playbook - mainly because i hate apple and already had a massive htc android phone so figured id give it a try. its good for its pricetag, but it seems to be the tablet that developers forgot. not much support from 3rd parties, the 'app store' is limited to business apps, and the games and other fun apps are all around £5 each, which seems pretty steep. they did introduce the ability to side-load *.apk files so you can download and install android games / utilities, but it wasnt quite the same. all in all, if you're a fan of blackberry, its good, as the screen is awesome, and its quick. multi-tasking is a doddle.
following on from that, i decided to dance with the devil and bought an iPad2... not much to say except its an iPad. it does what you want it to, its quick, clear, intuitive, but its still an apple product. theres still the pesky itunes (howevs i got around this by using dropbox to transfer all my media) - still no flash support (but then again it seems to be on its way out) and your tied into using what apple want you to use. the latest iOS stripped the native google apps, so no more google maps or youtube, and the apple maps is shockingly bad.
plus points... i feel like a hipster using it in starbucks.
i bought my wife the nexus7 on launch day, and its an impressive device (even came with a google play voucher) - if youve used - and liked - an android phone, then this is awesome. its running the latest ICS OS, and it works flawlessly. it came preloaded with a transformers movie, and the playback was second to none, and so clear and crisp! one major flaw for me is that it has no mhl support so you cannot connect it to your tv and use it in real time through there.
finally, my brother bought himself a kindle fire hd. its not too dissimilar to the nexus7 in terms of specs, but although it runs on android, its been heavily skinned to look like an amazon device. its not as easy to pick up and play, and it too lacks the google defaults (maps / youtube) although a nice device, id put it behind the nexus, but in front of the playbook. the ipad probably wins just purely because every developer under the sun wants to impress apple so tend to focus more on developing for apple, with an after thought given to android... let alone supporting playbooks