Glad to hear I could help.
Durability wise, Think Tank gear is great, their stuff is built to last. I read somewhere before that they believe that photographers generally replace their bag every 5-10 years and they build their bags with that in mind for the professional photographer (who might put their bag through more abuse).
I personally use a Retrospective 30 (next size up from the 20) - about a year old now. It's my main bag and I regularly put 1-2 bodies and 3-4 lenses in there. There are no signs of fraying, discoloration, or any other signs of use (aside from lint and such getting stuck in the velcro). Though it might get replaced by a Lowepro Pro Messenger I've been eying, but not because of any build quality issues - just some cool features I thought might be useful on the Lowepro.
Think Tank has a good warranty policy and customer service too, should you ever need it.