I have read it and no, I don't think it's obscene. It's well written and much of 'action' is implied rather than explicitly written. But I'm a fairly broad-minded individual and in any case people's sensibilities were quite different in 1928 when it was first published. In those days 'decent' people didn't talk about sex outside the (marital) bedroom and they certainly didn't write or read about it, let alone when the plot had such an obvious cross-class dimension.
I didn't see The Chatterley Affair, so I can't comment on that.