Are Envision monitors any good?

There is a store here that has a sale on a "20 flat screen with 1680X1050 resolution, 3000:1 contrast ratio, and 5ms response time for $169.99 after a $30 mail-in rebate. Wal-Mart has an Acer 19" for $168 that has less resolution, 700:1 contrast ratio, and 8ms response time. Both have three year warranties. Which is better? What should I get?