Banks is dying of cancer. They’re giving him less than a year. Well, snap. He wrote some very good SF novels, though to my own taste he’s fallen off lately. I found Matter to be a pastiche of his past work and couldn’t get past the first chapter; I believe he may have published another one since, but I’m no longer interested. The Algebraist was good, memorable in spots, but not up to par. His reputation was built on a series of very fine SF novels set in his “Culture” universe: Consider Phlebas, Use of Weapons, Excession, Player of games, Against a Dark Background. The last may or may not be in the same universe, but whatever. You could make a decent case for those five novels as the best five SF novels of the last 20 years. They’re all in the top ten by any sane standards (which is to say, you’re objectively wrong).
He also wrote non-SF and quasi-SF as Iain Banks, sans M. Nothing spectacular, to my taste.
Banks is kind of a slimy little left-wing piece of shit, who smugly boasts about getting excellent treatment from the NHS because he’s a VIP while the little people get treated a lot worse than a stray cat at the vet. He’s probably jerking off about Margaret Thatcher dying, so I won’t waste any time mourning the morally crippled little toad.
But he did write some fanfuckingtastic science fiction.