Old MTB's (region dependant) don't hold there value well. Unless you have a super rare color scheme Klein or say a Mountain Goat. This bike (it's a 1999 model) is too new for retro.
Big issues with this specific bike, Size, does it fit you?, Headshok, does it work, can you get spares. Brakes, it's got V-s, nothing wrong with them, but if you ride with others who are on discs, you will notice the difference; the frame / forks can be upgraded though with new wheels.
The frame looks well worn, so would look at the gear / drive train, for wear, and parts needing to be replaced; if you ride a bike hard, like it's designed for, getting a more than a year out of a groupset is doing well; MTB'ing isn't cheap.