For me it's not an either-or scenario. I use my Kindle when I'm bed, my Calibre e-reader (or preview, if pdf) on my MBP, and Moonreader+ on my Android phone. I'd say the ratio of usage goes like 10-15% for the Kindle, 25-35% MBP, and the majority of time Moonreader. I wish I could find a way to sync book status and highlights across the three platforms, but...

Koreader my friend