This depends on how fast (how frequently) a vibrating wire sensor needs to be measured.
AVW200-series devices are optimal for systems that exclusively require measurement rates slower than 1 Hz. CDM-VW300-series devices, on the other hand, are appropriate when measuring sensors at rates from 1 to 333.3 Hz.
Another way to consider the appropriateness of these devices is in terms of seconds. For a measurement period of 2 s or greater, use an AVW200-series device. For a measurement period of 1 s or less, use a CDM-VW300-series device.