Pros
I was recruited by the investors to help build Choose Energy in its earliest days. Not unlike those who came after me, I wasn't even aware that a consumer energy market existed before joining the venture. In the Valley, most of us either are or have been part of an early stage venture. Adtech, clothing, music, SaaS, PaaS, social media, etc are all interesting but you won't run into anyone at a mixer trying to build a marketplace and platform software for the deregulated energy business. So, it's different, and as my former co founder and colleague would say, it's HUGE! The energy market in just the 24 or so deregulated states represents about $500B in revenue annually. That's an awfully big market ripe for disruption.
To sum up, the pros of working at Choose are: the market opportunity, the team ( I hired most of the original, core team), the investors, and the vertical (you'll learn all kinds of new terms and business models to be sure).
I left Choose after helping to recruit the current CEO. I'm an early stage guy. I know where my strengths and passion live. After a crazy 2 years of high speed development and growth, it was time to let someone else with more experience take over the reigns during the next critical growth stage. I still love the company, the space, and my former colleagues. Given the chance, I'd do it again.
Cons
I honestly don't think that Choose suffers from the pressure of startup anymore than others do. Early stage venture is tough. Companies under pressure from investors and, quite frankly, ourselves, can run too hot, get ahead of ourselves, cut corners, or lose focus. Any of those debts incurred only compound down the road to create a sometimes difficult challenge for the team. I've experienced adversity at every startup I've participated in over the past 20 years. It always sucks, but we keep coming back because it's what we do, on occasion fooling ourselves into thinking that such adversity was confined to our last attempt.