The an excellent machine and is right up there with most of today's best. Not quite as deep or separates as well as today's top of the line, like e-trac, CTX 3030, V3i, etc., but 80-90% good. Certainly good enough that a skilled operator can use it very effectively and wouldn't be losing much if anything over today's $1,000+ detectors.
I just sold last week an excellent condition XLT that I bought new about 20 years ago. It went fast, like only a few hours fast!, for $325 locally on craigslist, but had a hard case and pinpointer. No extra coils, though. If it was really only used once or twice, the one you are looking at should be truly like new, and worth $350-400. I had my XLT for 20 years and never had a bit of trouble from my screen, no lines, backlight, all worked like new the whole time I owned it, 100% reliable unit.