HTC one is very easy to root.

I'd not suggest a Sprint version, though, as many ROM's just don't work on it. My phone is running a modified version of GE from Verizon and is a bit buggy, though the benefits still far outweigh the drawback (about 30-40% of the time the screen won't wake up right away after receiving a text - takes a couple minutes to work, or plugging it in will wake up the screen or a reset works. Depends how fast I need to read the text)