If the scanner cannot produce data of good quality, the added bit depth does little for the image quality. The most common modes are color transparency, color reflective, black and white reflective, and line art. With some flatbed desktop scanners, you'll need a separate, optional transparency unit to scan slides. If you need to scan negatives, verify this feature is included. This is often a subjective topic.
Image quality consists of resolution, unsharp masking, dynamic range, color accuracy, gradation.
These are the things that are characteristic of a scanner. In other words, we can't change these fundamental characteristics with the software. Some optics are of better quality and design than others. The unsharp masking circuit is critical determinant of image quality. This has a major impact on detail.