I have a Pebble and the screen is much too small for comfortable reading. It's okay for reading text messages and the like but certainly not for Les Miserables.
Unlike most folks here, I actually find the Pebble to be pretty convenient. Oftentimes, I have my phone either inside my purse, in a (tight fitting) jeans pocket, charging or underneath a mound of papers. Basically, not easily accessible. With the Pebble I can just view notifications, read SMS and screen calls from my watch. No need to take out the phone. The Pebble is also water resistant up to 165 feet so you could take it swimming (although I can't imagine getting signal that far below
). Besides, the price tag isn't bad. Costs about the same as a decent watch.