Hoping for some guidance with this.
I recently left the startup company where I was working as a senior backend Python engineer. The job had a lot of complications and the company suffered from a real lack of direction. Although things had gotten very dismal on an investment side of things, I did have the opportunity to learn a great deal of really new and interesting technologies and approaches to big data problems.
I entered the job search about two months ago and was successfully recruited at a Big Company (names changed to protect the innocent.) I was so stoked that this company was impressed by me, that I agreed to their first offer outright, even knowing that I may need to change some of the tools and approaches I worked with in the past to work with the large legacy codebase. (I realize this isn't exclusively an engineer's SE, so basically this entails adjusting back to older, generally weaker solutions)
At the time I had another very agile and exciting startup interested in me. I sent them a letter respectfully declining the position, but they were very persistent in trying to get me to change my mind. They wanted me to understand that they had worked with engineers who left Big Company very bitter for the very reasons I described, and that a position with them, "The Startup", would be much more beneficial to my learning.
Having just come from another startup that collapsed, its easy for me to gravitate towards Big Company, even though it means less money overall (the counteroffer was very competitive) and probably a bit of stagnation and adjustment at least at the beginning. The risks involved in a startup (my previous one routinely bounced checks towards the end) just seem too much to undergo once again. However, I am 25yrs old, reasonably early in my career, and feel that if there is a time for risk/reward it is now, before I have a family to feed etc.
Would it be respectful to request an NDA to sign, and then to ask see the balance sheet of this startup company? They have offered a very competitive salary, so at the outset I am inclined to believe them... I just cannot risk losing my livelihood out from under me again. What criteria, especially financial in nature, should an engineer with reasonable accounting sense use to determine whether a budding startup represents a better career opportunity over a stable, proved larger company (especially if the position at the larger company is already ensured)?
EDIT
Some great responses here! I am really grateful for the guidance from the community. Hopefully this question will be a valuable resource for others in the future, in my soul-searching the past few days I have found this situation to be more common than I expected.
For what its worth, I decided to honor my word and go with the Big Company.
I guess that's as much a matter as pricinple as anything else. I'm sure I would have had a lot more latitude in my decision had I not originally accepted.