There's a lot of chatter among ECRs about The Big Choice we all have to make: academia or private industry. Having worked in both sectors, I feel somewhat qualified to speak on the topic. First of all, it's not really The Big Choice that many early-career researchers think it is. The transition to industry is not in reality the one-way street many imagine it to be. I worked as a postdoc and then as an R&D scientist for a private company and then transitioned back to academia. Each time, it was the right choice. I don't regret taking a postdoc straight after my PhD. I don't regret going into industry for a few years and I don't regret coming back to academia. Some people's research careers are linear; my is more like a winding mountain path. Sometimes, the path seems to lead further away from my goal before turning a corner, sometimes the path slopes downward, away from the summit, and sometimes I stop on the path and just enjoy where I am.
The second consideration is the goals of academia and private industry. In private industry, the goal is, usually, profit. Your research must profit the company or, in the eyes of the company, it's not worth doing. The good thing about this is that if you can make a convincing business case for a new R&D venture, then you'll probably be allowed to do it.
The third consideration is money, both in terms of your own salary and funding available for research. I've often heard my US colleagues say that industry pays far better than academia. Clearly, that is generally true in the US. However, in my own experience in Australia was the reverse. My salary increased ~20 % when I returned to academia from industry (even more when you consider the increase in retirement contributions; Australian universities contribute 17.5 % on top of your base salary to your retirement savings). In terms of funding for research, it is much tighter in academia compared to industry, in my experience. You'll also have to fight harder for it in academia; there are so many academics out there with good ideas and outstanding track records and only a limited pot of money to fund research.
The fourth and, I think, the most important consideration is what you value. If you value increasing the world's stock of knowledge with a vague idea that somewhere down the track someone might find a practical use for the knowledge you've generated, then academia is probably the place for you. Conversely, if you value doing research that leads to direct tangible benefits (for your company or society more broadly), then private industry is probably right for you. I say probably because in the right academic institution or private company, you can build a career that has a nice balance of basic and applied research.
So, there you go. Four things to consider when making The Big Choice - even if it turns out to be only a Mid-Sized Choice.