I bought an HTC Vive about 3 weeks ago, so I've had it long enough to get a feel for it.
First off, compared to an actual monitor, the graphics are shit. They're pixelated terribly in most circumstances, and it usually has a "screen door" effect going on, due to the design of the lenses.
Performance can be an issue. Full disclosure on this: my CPU is not rated to run this, but has been mostly OK. I've got an overclocked G3258 CPU and a GTX 970 for graphics. On games (mostly racing games like Project Cars or iRacing) this has been fine, but when watching videos that use 3D, the CPU temp goes up to like 65C and there can be some stuttering. If the resolution goes high enough, the video framerate can drop to where it seems to be stuttering or maybe even dropping frames altogether.
The good: for racing games and flight sims, this is The Shit. You are IN the car, with full ability to turn your head and see everything. You have an actual sense of depth, distance and speed, and this all combines to make it so much easier to put the cars where you want them on the track. It's immersive enough that I don't even give a shit that the graphics aren't as good as on the monitor.
I haven't used any of the games or other features designed specifically around VR, like the stuff that requires you to stand and turn and all that crap, but for what I'm doing with it, I think it was worth every dime. That said, I would replace this in a heartbeat when another headset with better resolution comes out, though I'll almost certainly need a newer, faster system to make us of that.