Ya, that book is intense, kinda gruesome, and the end definitely had me surprised (always a great thing!)
SotA is a book of short stories he wrote, 2 or 3 (I forget) of which are in the Culture. The main one (the title story) is about a contact unit visiting Earth in the... 60s or 70s. It was really cool to experience his social commentary in such a more direct way than usual.