The VSU-2 sounds very similar to the VSU-100. Although the presumed speech decoding algorithm used by the TSI S14001A is replicated, there are numerous hardware differences which result in a slightly different sound.
Most notably is the use of a ~250khz PWM signal for audio generation. This requires less agressive filtering than on the original board, and results in superior speech which sounds less "underwater".
Listen to the examples on the main page
to decide for yourself.