I've learnt in the last 3 days that the best way to fail is to fail fast & fail publicly. Since launch, I've been personally answering every single e-mail from an user with an issue on their WooThemes account. This has given me so much insight into the kind of bugs that exist in the system and has empowered the team to prioritize the bugs accordingly.
Failing publicly also means that we've got some great motivation for fixing this sooner rather than later: our whole user base is watching us. I'm sure we'll be judged not by the bugs that were present, but our ability to deal (or not deal) with this situation.
At this stage, we're just being as transparent & honest as possible with regards to everything that is going on and must say that 99,9% of WooThemes users that I've interacted with have been very kind about this. I guess we could've delayed the roll out to do more testing beforehand, but that would've just delayed the project and it would not have guaranteed a bug-free launch. So we would've had to deal with this exact situation regardless.
If you're gonna fail, do so fast & publicly. And don't forget to react transparently & honestly; your customers will love you for that!