I had a 1999 XCR 2000 a few years ago, and nice as it was, the ride was very dated compared to a modern bike.

The biggest issues with the XCR series were you felt perched on them, as opposed to being part of them when riding, and bearing spares, you can still get the main pivot bearing, but getting it out could be an issue. One think I do remember, and the main reason for scrapping was the bike was noisy as well, and squeeks could be hard to diagnose where they were coming from. In the end it was cost effective to strip and sell as parts and upgrade the frame, rather than listen to the noise when riding (it was bad)

For brakes, if riding on your own, not having disc's isn't an issue, when riding with others who have discs, their absence will be noticed.

For climbing, never had any issues with it, did the job well, although not as good as a good HT.

for weight, a HT will almost always weigh less than a FS bike, from memory the XCR wasn't that light.

For value for money vs a new bike, with out knowing the price of the GT and knowing the BD bikes you are looking at advise would be hard to give.