My Windows 8.1 Pro laptop doesn't have TPM, so I can use bitlocker with either a USB key or a password.
If I use a password, it will be 20 almost random characters, it will contain no words in any language, it will have at least one small letter, one capital, one number and one special character.
Now, you will probably ask, in what environment you will use that laptop? It's a laptop, so I will take it with me everywhere. I am using bitlocker to protect it from:
a) thieves (most likely they will have no idea what encryption is)
b) friends (who know what encryption is better than me). We sit close to each other and I don't want them to see my personal projects.
Should I use a USB key or Password and why?
edit: In terms of brute force protection, how much better the usb key is?