The Surface Pro, with OneNote, works extremely well for this, more efficient than paper. OneNote is buggy and crashes, and the Surface is sometimes slow---so it isn't perfect---but it is still better than paper. High-quality pen input (except at the screen edges), different colors, copy-paste and undo.
For reading pdfs, the widescreen is annoying and claustrophobic, and I haven't found any Windows PDF reader that is comparable to Apple's Preview application. Occasionally I've "printed" pdfs to OneNote, to read and edit them there, but this doesn't work great. (You can't drag pdfs into OneNote because Windows and pdfs barely work together at all.)
For reading pdfs, the widescreen is annoying and claustrophobic, and I haven't found any Windows PDF reader that is comparable to Apple's Preview application. Occasionally I've "printed" pdfs to OneNote, to read and edit them there, but this doesn't work great. (You can't drag pdfs into OneNote because Windows and pdfs barely work together at all.)