Was it particularly well written or optimized in very clever ways? Bob Miner was supposedly a beast of a coder from what I've read, so wouldn't surprise me.
Oddly enough, I never met any of the coders. The entire code base turned up on mag tapes from Belmont, CA. I was working in Toronto. I was very much a newbie, so I didn't form an educated opinion on code quality. There were very few bugs, I do remember that.
There was a lot of code, about 1.5 million lines over two version of Oracle, which included a bunch of applications as well as the RDMS.