Last year I bought my Scott Spark RC 900 WC ($6,000) sight unseen and having never swong my leg over a Scott bike. That being said, I did do all my research and put my hands on a bike of similar size and geometry. I also knew exactly what I was looking for. So yes to add to @Kuttermax, the exact “fit” is less critical than road per se as long as you get the correct frame size, but it will depend on intended use (all mountain, XCO or XCM racing, etc.), your terrain, bike’s geometry, your riding style and “feel”. If you’re an experienced MTB and can do all your own research then you’ll know this. If you’re newer, then a good bike shop can help.
Also, the Specialized Brain is love or hate with little middle ground, so I’d definitely test the brain before you buy.