pure nostalgia for me - I read a few of this series when it first came out in 1970/71/72 when I was 15-17, and they really turned me on (that was the current phrase then) to short stories and what they could accomplish. I came across this in the library where I work (well another site, as we don't have fiction at ours) - think I missed this one, but it has one of my favourite authors, Isaac Babel in it.
The Babel one (only 1) was good, but slight. Sean O'Faolain's ranged from adolescent boys and first sexual experiences to more sophisticated games of adultery. Both were excellent, and moved beyond their subject matter to more poetic epiphanies. I loved Nadine Gordimer's - 5 stars for both - exploring the South African experience in the 60s: sharp stuff. Shiva Naipaul's were more comic, fun - the pretensions of Trinidadian shopkeepers and councillors and their daughters and wives.
What a great series this was - came out 4 times a year and featured two or three stories from four writers. An excellent showcase. Someone should revive it now.