Ebook: technology question

I am about to face a pleasure of a decent amount of daily commute to work (the farewell gift from the employer I am leaving!).

So I was thinking about using this time productively, if not for reading but at least for revising the curriculum.

Which device are you using for reading ebook on commute?

Is the CFA content downloadable to Android devices?

To Kindle?

I would go out and buy the right device but want to make sure it really works.