See Links to these web sites for scanner specifications. Each of the film scanners in the table has many fans. A higher price does buy more scanner, better optics, infrared dust reduction, better software, but primarily you get better dynamic range, giving deeper noise-free detail from dark shadow tones in slides.
Dynamic range is quite important for slides, but less important if scanning negatives.
But the dynamic range spec is not shown here, because the advertised number is unfortunately only marketing hype. There are no standards for advertising this value. It is a totally meaningless number as advertised. Don't assume 3.6 is better than 3.4, or that either is achievable. It is not a performance spec, the scanner was not measured.