Being big can be good if you want to stomp on something. Being small can be good if you want to run away from something. Big is good for credibility. Small is good for flexibility. Big is good for hiding in. Small is good for not being able to hide.
Seth Godin wrote a post on companies not being able to use being small as an excuse and I totally agree. Small is totally a weapon. Anyone whose used moo.com, or has a Moleskine notebook should know the attention to detail a small company can pay to costumers and suppliers.
Any anyone who has worked for a big company knows how frustrating it can be to get everyone to work in the best interests of the people who make us your community – i.e. the consumers, users, suppliers etc.
I would take David over Goliath any day, slingshots are fun.