I have two of these exact same models, sold by Amazon under a different brand for $60-$70.
Lots of different settings depending on your position and desired angle. Post surgery, I use this in bed at 180/60/180 degrees and can comfortably work for hours. Wish it was a little bit wider, but my 15" wide-screen laptop and phone (for teleconferences) fits just fine. Also, if it was any wider, it would stop being useful on sofas.
The second one I use in a zero-gravity chair at my office - with different settings. There I also need pads under my shoulders to prevent arm strain for prolonged use.
They've held up well, with lots of use over the past 2 years. Still stable. Folds completely flat and fits in your carry-on. I wish I didn't need them that much...