I am in a similar situation, so I can't offer you any opinion from experience, but I'll share the reasoning I used in making my decision:
A large company can afford to hire you as an investment. Most lower-year students can't offer a whole lot to a company, but to BigCo it's like buying options in you as a future full-time employee. (Not that you are not obligated to keep going on full time, but many students will) I've heard many stories of people spending their summers at the big companies, getting paid well, but working on things that never saw the light of day.
A small company, on the other hand, can't afford to do that. Any work you do will have to be important to the company.
A large company can afford to hire you as an investment. Most lower-year students can't offer a whole lot to a company, but to BigCo it's like buying options in you as a future full-time employee. (Not that you are not obligated to keep going on full time, but many students will) I've heard many stories of people spending their summers at the big companies, getting paid well, but working on things that never saw the light of day.
A small company, on the other hand, can't afford to do that. Any work you do will have to be important to the company.