A:Answer I have the HTC Vive and had racked up enough BestBuy reward points where the Rift bundle was only $100 so I figured why not. Having both systems, they are key differences. The HTC Vive is really for room scale play. You need a fairly large space to get the full benefit. The Rift works best in standing or seated mode and its sensors are easier to position on a desk if you're going to play a game in a seated position. Quality is about the same which makes sense since both systems are the same resolution. Tracking is about the same for both and so is performance. The Rift headset is lighter, but does not accommodate eyeglasses easily, where the Vive does.
The setup procedure for the Vive is easier even though it is a more complex setup. If I were forced to choose one over the other, I would choose the Vive, but the Rift has the better controllers - the Touch controllers are awesome - if HTC did something similar, it would beat the Rift in practically every category.
I guess this is a long way of saying that if you plan to play VR in a mostly seated or standing position and mostly facing forward the Rift is fine, but if you want full room scale freedom then the Vive is your best option. As far as disappointment, for me they are both fine provided you spend the time to adjust and configure your system to get the most out of them. With Steam, most of the titles are cross platform.