I don't know your exact usage scenario, but if you want to do a lot of handwriting, tablets like the iPad are not as good as convertible tablet PCs.
The iPad (and most other tablets) lack an active digitizer, so you lose accuracy and pressure-sensitivity when writing. The screens in these tablets are great for finger input, but most of them are not optimized for pen input. There are a few exceptions, such as the Galaxy Note and HTC Flyer (which do have active digitizers), but those are the exception rather than the rule. On the other hand, all convertible tablet PCs (like the Thinkpad X220t) have either Wacom or NTrig digitizers built in, so the writing experience is much better.
Plus, on a convertible tablet, you can run windows, and that means you can use the best note-taking app of all...Microsoft OneNote.