I notice more and more start-up companies that I do business with are offering various levels of support, ie. the more your willing to pay the faster they may answer. I find this to be such a flawed concept... you purchase their paid service (open source is clearly different) at a profit to the company, I feel it's their duty to provide free decent support - after all it's their service!
Think about it, how often do you really call on support? I mostly do when things go wrong and depending on how good the service is this might be less than once a year, I've had services run for more than 3 years without having to call on a support team once! The majority of places offering a service to you offer free support, some of the support is absolutely excellent at helping you out and do so with a smile, one major example being hosting companies like Burst, Softlayer, Leaseweb, etc
Waiting for days for a "free" support (if even available) reply not only turns frustration into anger it makes customers want to find an alternative, a company who cares about them and will even pay more for the product if it means supports readily available. Truth be told I've worked in support, yes it becomes busy but their is simply no reason not to assist people in a timely manner (if you can't - get more staff or check why your getting so many requests) or at the very least provide proper communication for them to know whats happening behind the scene's.
As I write this I'm waiting on a support ticket answer, one part of my site is down and it's been days, why purchase a support plan when it'll just make them rich when I don't use it for the majority of the time... almost feels like they stretch it out to entice you to purchase support, it feels like time to find an alternative! *update* I found an alternative (sms messaging API with free "premium" support) and implemented their API in less time than the 4 days support took to respond with what was a question leading to another 4 day wait... they (and a popular cloud based security provider) have lost all my feature revenue, might not be much but combined with all the clients they lose in a competitive environment due to this, pretty sure it'll hurt in the long run!