Yes that is Nervex. ^

Your bike appears to be in very good original condition.
It looks like a 25-1/2" bike to me, not a 27" bike.

$300 is probably about the average price, but the prices for SC's are all over the map (I've seen them go for $25 to $450).

Some people disregard them as commonplace/ mid-entry level bikes, and others regard them very highly - even over other much more expensive bikes.
The price you'll get depends on what sort if a buyer you find, and how long he has been looking to find a decent example.

If it is not too small or too large, you would do well to hold onto it yourself: It is a true classic with stellar ride quality.