Got a 3-9 x 40. Stays on x7.
Favourite scope at the mo is a 6x40 with German No.1 reticule, so obviously stays at that.

What has happened is that the price of zoom scopes has come down over the years. Now the manufacturers know that customer's look at features as "value for money" and (sadly in my opinion) won't buy a fixed scope. Don't get me wrong - reading some of the replies, zoom is great (just as in photography), but using a fixed value mag will get you used to the range. You get to "know" your scope.
I think it would be great to have some high quality glass in some fixed range options in addition to the x4. I'd go for x6 or x7 as my option (x10 too much for me at airgun ranges).
I'd want better optical quality over cheaper price, and yes, AO would definitely be a nice option.