The app and guide are very similar to a native X1 box, so it's really a natural transition and the video quality is great, but that's where the similarities end. There are a few annoyances that the developers could easily overcome, but have yet to address. The first is that when bringing up the guide, you cannot stream in the background, while you're searching the guide. I know it's possible, because if you bring up the "last watched" guide, the channels overlay on top of the stream that continues playing in the background. The second is that if you watch a DVR or On-Demand show, when it's finished, the stream just goes dark. On a native box, it reverts to the last channel watched. It's a problem for someone who like to fall asleep with the TV on. It goes from ambient background noise to dead silence, which for me, means waking up to put on another channel. Also, when watching from a DVR program, when you fast-forward or rewind, you cannot see where you are going. You have to pause first, note the time, then fast-forward 4 minutes (the average commercial break, sometimes it's different). It's difficult to catch it at the correct spot and you end up spending more time making minor forward or back adjustments.
Just a few tweaks and this platform would be great, but it's absolutely a work-in-progress at this point.