I’ve worked at huge companies, merely big companies, medium-size companies and small ones (where I work now).
There is in the popular mind more prestige in working for large companies with recognizable names. It’s particularly true in the tech industry — my industry — but somewhat the case in any field. Having worked, though, at companies of all sizes there’s much to be said for how working for a small company hones your skills and your approach to problem-solving.
When I worked for Transunion (a merely big company) there were dozens of people I could turn to for assistance with problems, experts in their fields, some of whom even did the same job as I did.
Where I currently work, here’s who I can turn to when I am stumped or at an impasse: no one. Either I figure it out or no one does. There just isn’t anyone else around with the necessary skills to bounce ideas off of, to ask for assistance, to turn to when I’ve hit a wall. Sure, I can hire consultants (and sometimes do) but they are expensive and unknown and often unreliable.
So I end up exploring many areas, learning diverse sub-fields, doing tasks and taking on responsibilities I’d never get to at large companies. I simply must understand many areas from the ground up to get my job done. At medium and large companies, often there are entire teams I can just outsource parts of important jobs to, that in fact I am not even permitted to venture into because the task is under other teams’ remit to take care of. At a small one, I outsource them to myself, just at a later time.
It might not be true for everyone, but I’ve certainly learned more and more deeply working for small companies than I have for large or medium-sized ones. I wish that experience were more valued in my field.