I have bene using the 16x42 IS for a while now, and here's a summary of what I think of them.
Overall, they are very useful. I can see 1.7x the amount of detail as I can with my top-quality 8x binoculars. It's not 2x, because the Kite are somewhat inferior optically (see later) but there is no doubt I can see many more details.
On the negative side, they haven't become my go-to binoculars. I carry them in addition, and not instead, to my 8x32 or 7x42. This because they are less versatile, and a bit inferior optically. Less versatile because they are not very easy to use to find active birds in canopies. Further, compared with my top of the line 8x or 7x binoculars, there is some of the snap of the image that is missing -- if you are looking at something you can identify well with an 8x, you will prefer that view than with the 16x.
But replacement of my 8x binoculars was not the goal. I wanted something that would replace a scope, as I did not think I would enjoy carrying a scope and tripod. In that respect, they work quite well.
Optically, they have three weak points compared with my 8x top binoculars.
First, they have some CA. But the CA can be controlled by perfectly centering the pupil in the ocular. It's a skill that you learn using them; don't be put off if the initial view is so-so.
Second, they suffer from glare. My 8x and 7x are superb, and one forgets how normal binoculars behave when pointed at dark vegetation with a bright cloudy sky right behind. The Kite will remind you. But I notice the glare issue only rarely.
Third, they have lower contrast. But the overall contrast is still very good.
They also have a couple of real advantages.
First, they do work quite well. The stabilization works very well, and you can see a lot more. I estimate the benefit is a 1.7x benefit.
Second, they are very practical. They are not too heavy, they are very very robust, rubberized, they are practical in battery usage (don't run it down often, no button to keep pushed, self shut-off when pointed down). I carry these around quite a bit; I would not be as confident carrying around more fragile binoculars.
Concluding, I carry these around in about half of my outings. In the outings in which I have them, they are crucial for some ID about half of the time or more (the last ID I got that way was spotted sandpiper; from the distance where I was, I would not have been able to make the ID with my 7x). I normally carry the 7x or 8x on my neck or bandolier style; I then switch to the Kite, which I carry in a backpack, as needed. The drawback is a bit more weight on my back, and more importantly, a bit of additional complication (take the Kite out of the case, use them, put them back in case, put the case in backpack.... ).
Now that I have them, I do not dream of carrying a spotting scope.