I used to use a Wacom bamboo. Still have it but don't use it. To be honest, these things become unreasonably bothersome if you use them only for annotations. You'll need to change the way you consume and process content. But if you're already scribbling over screenshots with your mouse, go with any of these. The technical specs like pen angles, surface textures do not matter a lot unless you're an artist or pedantic. Instead, look for ease of connectivity, software support etc.