KISSMetrics or Mixpanel? Why I Made the Decision Before Seeing the Product
matchist.com
matchist.com
Also, maybe KISSMetrics make themselves this initially available to everyone - which is why they have the time to respond quickly to you initially, but then backend support is slower. Or all levels of their support are good because they're an older company and have had time to evolve to that.
You can't really know.
MixPanel did respond in the same day, they just weren't available immediately.