@leon_p_smith @mildsunrise @guenther
Latency is the most important parameter.
Even under the best of conditions you're going to end up with latencies in the single digit millisecond range (number of samples in a buffer divided by sampling rate ×2 for the round trip + overhead). E.g. 96 kHz, 512 samples (32 bit, 2 ch makes a page) = 5.3 ms
Now that might not seem so bad, but adding as little as 5ms of latency in the monitor signal of a vocalist will "make them suck".