In the spirit of thanksgiving, I'd like to drink the kool-aid a bit and note the perks of working at a big 4 firm, perks that you can't get at most other companies -
a) Flexibility - If i wanted to, I could work from home unless i had a scheduled meeting somewhere or a commitment to be at a client. If i wanted to, i could "work" remotely, but be out at the golf course instead (Thank you, almighty blackberry). Granted, you won't get this your first few years at the firms, and you still need to put in the work (late nights to make up for the amount of time you slacked off), but a lot of ex-coworkers have expressed this lack of flexibility as the biggest intangible they miss.
b) Recruiting - Yea, you can do this at every company. But because of the volume of college students we hire yearly (full time and internships), the opportunity to go back to college and participate in full fledged recruiting activities is something you have to appreciate. Looking at the changes in your alma mater every year, eating out at your favorite cafes in college on the Company's dime, the nostalgia that overwhelms you overtime you go back, good times.
c) Peers - Your peers are more fun your first few years at the firm. Then they all leave, and you are stuck with the people who are way more serious about this job. But think of the number of people starting right out of college, and working together, and b*tching together. Good times.
d) Mileage, cellphone reimbursement - Drive a 120 mile roundtrip, collect $60 for the day. Granted, you are running up the miles on your car, but it's pretty sweet to never care about gas money. And with the amount of data we use up with our blackberries, with bills averaging about a $100, that's another bill we don't have to worry about.
I'm sure there's more, but these are the only ones i can think of right now.