Yes, I agree with him.
The main problem with the other game quite a few people in this topic are bringing up; Planescape: Torment, is that while the story is amazing, the setting imaginative, characters extremely well implemented, and so on... the actual 'game' part of it is shoddy at best, similarly its use of the Infinity engine was limited in places and downright archaic in others.
So while Baldur's Gate 2 may not boast quite as impressive a story, it more than makes up for it in other departments. Plus saying that its story 'isn't as impressive' is a disservice, since Baldur's Gate boasts its own fantastic tale and interesting characters as well.
That's my take on it anyway. As an overall experience and rpg, I'd say yes, Baldur's Gate 2 is the champion. If you were to ask about individual elements, which rpg are better at certain things, then there would be more debate. But overall? BG2 wins in my mind.
It's also nice to see the game still prompting so much debate and getting so much attention ten years after it came out too! If that isn't the hallmark of a solid experience to have left such a lasting impression, I don't know what is!