If you run a business, I really don't understand the appeal of sharing a crucial part of your data (for web based applications / services) with a third-party (Google, Amazon etc. or maybe even Segments in the future) that may at some point compete with you ... especially when you can just parse your own web logs ...
Yes, it’s possible to have your engineering team build its own version of Mixpanel. And it may actually cost you less than it cost Mixpanel to build Mixpanel because it’s more focused on your needs. But you know who has already built Mixpanel? Mixpanel. And they’ll let your business use if for a couple hundred dollars a month. Starting today, not six months from now when your version would be finished. Better still,…
The raw data is with you. You don't need to wait for 6 months but launch a version with limited features and can continue developing it slowly, until it achieves whatever feature parity you are aiming for.