Any stylus is fine, I personally used evernote/penultimate at the time... but now, having started work and been recommended... OneNote on the ipad feels pretty strong. Not to mention it is easy to sync with your laptop/computer/phone etc...
Initially I started with an iPad, however it's a ball ache to use it for notes as you go. You get distracted, you have to format stuff, you're worried about the battery. It'd be far easier to just use a notepad and then type the notes up later. Going over these notes helps you to learn the content.