While it may seems to be better to take the 300 daily on the surface, it is definately not the case. 300$ daily seems better in terms of limiting your self and 'in the long run' since hopefully you will live for more than 20 years. But these problems can easily be circumvented. Firstly, with 2 million dollars, you can take 1.8 million and put it in your savings accounts. From there you can build up interest to make money on your money. the rest you can spend however you like.
Secondly, with any amount of money you will need to limit yourself. If you have even an ounce of will, you will be able to restrict yourself from spending all your money.
Thirdly, to everyone saying invest your money, that is not necessarily a good idea. Investing in stocks can make you lose all your money. If you are going to invest you need to invest in HARD ASSETS that way you can never lose your money since you have the physical product. Gold, Silver, and Fancy colored diamonds is definately the way to go. Also Real Estate would be a good option, buying and selling houses can make you a lot of money.
Over all based on investments, will power, and modern day banking, I would personally choose the 2 million dollars straight up and I would hope you guys do as well.