I don't have any data but as a secondary English teacher I can offer my experience. I work in an academy in London. We set by ability across all subjects and get the best results on our borough across all ability levels.
That said, our school is a well known exam factory, where both students and teachers are pushed to the berg limits, sometimes beyond what I think is healthy or sane. Plus all focus is on academic performance so we are very weak in extra curricular, performing arts and sports. (Sorry if this detail seems irrelevant- I am trying to give context of our high performance: it definitely comes at a cost).
I have only taught mixed ability English at KS3 and I found it extremely difficult, and so did the students. I don't feel that any ability level was getting the best out of my lessons. Perhaps if I had been more experienced at that stage (it was early on in my career), and better at differentiation, it would have been more successful. However even now that I am much more experienced, I find the concept of differentiation for wildly varying ability to be something of a myth! I can differentiate well within the context of a reasonably similar ability group (even in top and bottom sets the ability is very varied), but to teach a lesson on, say, Great Expectations, to a room of students in which some only understand 30% of the vocabulary and others have devoured the whole book in their own time, is, for me, impossible to do well. Maybe that is just my personal failing, but I suspect most of my colleagues would be similarly stumped!
I know setting does come with disadvantages, in particular to self esteem. However, in my school at least it certainly cannot be said that teaching in the lower sets is unambitious. We genuinely put our very best and more experienced teachers with the lower achieving students, and we teach them high level skills and concepts. One of the most amazing moments this year was on results day, when several of the students in our lowest ability classes got 6s and one boy even a 7, in English Lit. I am talking to very lowest ability classes here- this boy has significant SN was predicted a 4! (Ok maybe the result was a total fluke, but other children in low sets achieved plenty of 6s too). And at the top end, our cohort for Eng Lit (both year 10 and 11 sat it, so 440 kids), achieved over 30 level 9s and many more 8s.
Anyway, my experience is entirely linked to my own school, but I don't think I would ever want to teach in a school which didn't set.
Apologies if some of this is garbled- have been up all night with sick baby 