Brentwood is a city in flux. During the boom of 2003-2006, it was nearly impossible to buy a house in Brentwood without a lottery. However, with the "snap-back" in real estate, Brentwood is suffering one of the highest forclosure rates in Contra Costa County. The vast majority of the houses in Brentwood were built in the last 5 years, so it is a great time to get a brand new house for a good price, however expect to have at least 3 completly abandoned houses on every block in town. The crime rate is low in town, however, it may change because of all the abandoned houses.
PS - Also consider you may have one of the worst commutes in the Bay Area if you need to drive on the 4 freeway.