It seems comfortable as you describe. The first things I'd check is that:
- Your upper body is supported by your hips and your back isn't becoming rounded,
- Your head is where it should be, not extended forward, and
- That your keyboard and screen are correctly positioned.
Having said that, I assume you're frequently typing, not just watching the screen. Ideally there'd be a keyboard located just above your legs, like on a home-made step or by setting up some yoga blocks between or alongside your legs, to set the keyboard down on. Then the monitor or laptop screen placed on the coffee table so that most of the time you can simply look straight toward it without tilting your head up or down. If it tilts down a bit at times, I suggest a tucked-chin position to keep the weight of the head from dangling forward at those times.
My expertise on this matter is from 4+ years as a fitness trainer dealing with all sorts of posture problems. One rule of thumb I have: if you can feel the weight of your head while you're working (or watching TV), or there's any feeling of muscles active in your back, some portion of your body may not be aligned well at the moment so adjust as needed.