I use and love the Kindle app. on my PCs. I will probably get a Kindle eventually but the app works so well I doubt if I buy a Kindle for myself it will end up being a present from my wife or Parents.
Using the Kindle app is a dream come true being I grew up watching Star Trek and was amazed someone could read a book from a computer screen. (Its the same reason I only buy flip open cell phones. I always use the Star Trek Communicator beep for my ringtone! Yes I am a nerd...)
I have the basic $100 B&W small screen Kindle. I can’t recommend it enough. The “electric ink” uses zero energy after changing each page. A battery charge lasts literally for weeks. It’s perfect for trips, since you can have an entire library in the little machine, instead of hauling a bunch of books along. I love mine and have no intention to upgrade to a more power-hungry color Kindle Fire.