I've had mine for two years. My original one was a loaner, and then I bought my own about a year ago. I had one of the faulty potted sensors, and it failed at the beginning of January. The company requested I return it, and they promptly sent out a replacement unit. I have no complaints about the service.
I LOVE the computer. The display is unreal. It is bright enough, on medium, to serve as a third backup light in a cave exit -- I can say this with authority, because I did a 48 minute lights-out exit in my Full Cave class, and the gauge threw enough light so that I could see the rocks coming and didn't have to swim with my arm out in front of me. The screens and menu are extensively customizable. VPM seems to be a very rational decompression algorithm.
I've had a little trouble getting the device to gas switch for me, but tapping it with my lighthead has worked, and I'll admit I'm kind of overloaded at those points still, and probably not as effective as I could be. I also wear VERY thick glove liners, which probably diminishes the effectiveness of the tap.
I would like better logging software. I bought an outside vendor's software that is supposed to be compatible with the X1's output, but I've never figured out how to export the files to it. The existing software does not make it easy to sort your dives, to be able to pull out cave dives, or trimix dives.
My X1 is power-hungry to an annoying degree. My husband's doesn't seem to be nearly as much that way. I don't know what the difference is. The best way to live with an X1, in my experience, is to put it on the charger whenever it's not in use. Unlike other computers, you can't set it on a shelf for a week or more and expect to have it usable when you pick it up.
Overall, I very much like the computer, and I would buy another one.