Keep it. My Diamond Back Ascent is full of XT and LX - I'm looking at a repaint after winter (had 1 repaint). It's 28 years old at least. It's a good frame for XC blasts.
I had to do a double-take when I walked past a railway station the other day. Locked to the railings, with various degrees of security/faith in human nature were:- 1) a 90's rigid 26" Kona MTB of some sort, 2) a Raleigh Stonefly 26" rigid MTB, 3) a rigid 26" Giant MTB of some sort, 4) a lugged frame 700c Raleigh Pioneer, 5) a lugged frame 26" rigid Raleigh Maverick MTB, 6) a 26" rigid Apollo Energy MTB, and 7) a Raleigh Mustang 26" rigid MTB complete with chrome steel wheels (and it's own gravitational field I expect!).
Despite some of these bikes knocking on for 30 years in age, possibly even more in the case of the Maverick, it's interesting to see how they are still very much favoured for utility bikes, and that their riders have not replaced them with more modern bikes. I would still not leave a steel GT MTB locked up at a station though!