Great write up by 50shooter.
I know you didn't ask, but I'd add two more brands to your list - State Arms and Bluegrass Armory.
State Arms has a reputation for making accurate rifles at a reasonable price.
Bluegrass Armory Viper (which I own) is similar in appearance to a Barrett, less money, and usually more accurate. It won't have the name recognition (and therefore resale value) of a Barrett, but IMHO it is a better value. One word of warning though, Bluegrass is a very small operation, and 2 years ago their wait times were 6 months. I can't imagine that its improved given the current climate. Also, when you talk to them they tend to be VERY optimistic in estimating delivery times.
BTW - be sure to leave some $$$ for scopes, ammo, and accessories. For scopes - Nightforce if you've got the money and Supersniper if you don't.