As far as I know, security has always been one of Cisco's top priorities which is one of the reasons they have been so strong in the enterprise market. It's almost inevitable at some point that bugs like the one in the link here pop up but I haven't heard of any backdoors or nefarious practices from Cisco in the past.
Cisco has been strong in the enterprise market because they are good at marketing to the enterprise market, and providing certifications so that they can ensure a labor pool for IT departments.
Part of the marketing is talking about security. It's unclear if the reputation matches reality though.
I say this as someone who has become super disillusioned with Cisco, as the thread originator has. But this is mostly because of their switch products, pricing, configuration management, and end user software. I don't have much experience with their security. Though I have no reason to suspect that it's the least better than any other companies' security based on the amount of patching and their default configurations.