Just be aware that the SCC-1 is a internal ISA card and you won't be able to use it on machines without a ISA slot.
I wouldn't have it any other way.
Why not grab a SC-55 or SC-55 MKII Sound Canvas? They are nice units, plenty around as well, come with a nice LCD display and have a line input for e.g. Sound Blaster speech and also a headphone port + volume knob at the front.
The main reason I wish to replace my CM-300 with an SCC-1 is because I dislike the external units. They are inconvenient for my needs and my workspace. It's the same reason I bought an LAPC-I a couple of years ago, and am just now getting around to selling my MT-32. But thanks for the suggestion, anyway.