I've been working at my current job (a medical device startup) for about 4 years. I was one of the first employees and have been able to help bring the technology from a proof of concept to an actual product that is currently in large animal trials and ramping up for first in human studies. I've learned a whole lot during the course of my work there, generally like my colleagues and boss, and think that my contributions are both meaningful and valued.
However, in recent months I've been a little frustrated - most of the problems I am tasked with solving now are important but not interesting problems. There's little fundamental scientific work left to do (until we start developing follow-on products) and my role has been more of a scientific resource/sanity check for fairly straightforward optimization problems. That being said, I have never commercialized a technology before and there's still a lot of the sausage making that I have yet to learn. Staying with the company through a successful first in human trial would definitely look good on my resume, with the only real thing I'd still be missing would be building out a sales force and product launch (something I have relatively little interest in becoming familiar with).
I haven't been specifically looking for a new role, but recently an opportunity fell in my lap. I am being considered for a more senior position in a much larger organization (a large and well heeled pharma company with a combination devices unit they're building out). I happen to be acquainted with the hiring manager who would be my boss and liked him a whole lot, and I think the feeling was mutual. The role would probably involve a lot of basic research and leading a team doing the kind of stuff I'm good at. The resources available to me would probably be effectively limitless (within reason). The downsides? First, I'd be working in a space I'm not as familiar with and am not sure I'd be able to excel immediately. Second, it's about an hour commute vs. half hour currently (though with an option for 1-2 WFH days a week). Third, I'd be walking out of my current role that is, frankly, fairly comfortable and allows me to learn about a lot of functions that are hard to experience in a large company.
The pay's a lot better up front (figure ~$80k/year higher) but without the unlimited upside of my current startup stock options. The responsibility would probably be a lot more, too, and my wife and I are already stretched thin at home now that she runs a division with ~40 people reporting through her. But it's the first opportunity to come my way in the last 4 years that actually made me consider leaving.
So... for those of you who have made an unforced career move, how did you decide to pull the trigger? How did you balance the known of your current role with the potential benefits of a different role? Did you feel bad leaving behind a project in which you'd invested a lot of effort, and a team you liked?