This page is a list of Sets that go above and beyond that minimum requirement - Sets who actually try to make this process as painless as possible, and who give the Bar a good name. If you think a Set deserves inclusion on this list, email firstname.lastname@example.org outlining your reasons, or just leave a comment below.
In no particular order:
QEB Hollis Whiteman
In 2012 they have gone out of their way to keep candidates informed, with emails outlining their process and timetable, even before inviting anyone for interview.
2 Hare Court
Detailed post on the Pupillage Pages outlining their process, prompt, courteous rejection emails.
5 Essex Court
Provided an initial update email outlining how their process worked, prompt courteous rejections, and detailed feedback about the applications they received, why some succeeded, and what to avoid in future.