Sean Connery did a great job and made the character his own.
BUT
his version of Bond wasn't the version in most of the books, and it was by no means definitive. I say most because the later books moved more toward what Connery portayed (they were also not as good, IMHO). OHMSS was a return to what Bond could have been (and was in most of the novels) and in that respect Lazenby was a better Bond. On the other hand, Connery's bond maintained the womanizing superman much more steadily, the choice to humanize Bond was an interesting one. Anybody who hasn't seen it and considers themselves a movie buff should at least rent it, to see a different (but also good) interpretation of Bond. A way of explaining it is that Lazenby's Bond is more mature, he's a more human character. I can't imagine he'd go back to acting like Connery, Brosman, or Moore (Dalton doesn't count as a Bond) after that movie, but it's easy to envision them maturing to become him.
Personally, I think Brosman was better then Moore, Connery was better then Brosman, and Lazenby was as good as Connery but in a different enough way that I can't pick a winner.