I feel similarly; I started my career at a BigCo, didn't get much out of it, joined a fairly young company, with (1) more responsibility than someone of my tenure should reasonably have due to (2) high tolerance for failure and (3) they didn't have headcount for the specialized role I was doing. Going back to a BigCo, the experience there was utterly invaluable. I realized that my first go round I had absolutely no idea what I should even be trying to get out of it. This time's different.

There's huge value to getting the lay of the land.

I think there's a similar dynamic with consulting - ThoughtWorks / Pivotal Labs type places. You get shunted around between many different projects, there are never enough people, so there are opportunities to take more responsibilities, and things are often a bit fluid, because a consultancy coming in tends to (should!) crack the organisation a bit. There are downsides to all of that, but it's also a way of getting wider faster, if not getting a lot deeper.

I worked in Pivotal Labs for about two years. It is an amazing place to learn the craft.