Which 1604? The original, the VLZ, the VLZ Pro, or later?
I worked for many years with the 1604VLZ as a live mixer, in the studio, and as a broadcast/movie production sound mixer. It was a solid middle-of-the-road mixer for it's time, though these days it is a bit obsoleted in sound quality compared to many of the newer units out there.
My only complaint is that the sealed trim pots on them are semi-notorius for getting noisy over time, and being fixable only through replacement of the pots (they cannot be cleaned). Other than that it had served me well for many years on the road and in the studio.
G.