How do you know Gmail doesn't misclassify valid mail as spam? This is what terrifies me about the thought of using a spam filter: false positives.
That said, I openly list my email address online (and have with the same address for 12+ years) and have really average filtering that leaves me deleting spam that slips through and chasing down false positives.
I've only found three or four false positives in the five and a half years I've been with GMail.
For instance: IF X email is in the spam folder AND contains any of the words (Cialis, Viagra, Rolex, etc...) -> Move it immediately to the trash.
This cuts down the number of emails that stay in my spam folder by a huge margin, and makes it much easier to check for false positives.
That being said, I no longer even bother checking. I've been with Gmail for 5 years and I've never had a false positive.
That being said, you still have a point.
aside: for poor man's obfuscation (like in my HN profile) I do jhl805atgmaildotcom ... my belief is that this is hard to extract automatically.
([^\s]+)\s*[Aa][Tt] *([^\s]+)\s*[Dd][Oo][Tt]\s*[Cc][Oo][Mm]
Yours is no harder to pull out automatically than the examples in the original article, and the above regexp took me under 2 minutes to write and verify. It's not your "obfuscation" that's saving you, it's gmail's spam filtering.
Found one false positive in the last six months, and even that was a mailing list so didn't matter.