The clear cut difference is load time. Avg boot time to windows on an SSD is few secs. On an HDD its a few mins. Because the various data to load windows is spread out over various sectors on the HDD platters

SSD and HDDs can generally be the same size if used for laptops. The main difference between the two is weight. SSD generally have lower storage capacity than the normal run of the mill HDDs. The main reason ppl use SSDs than HDDs for Windows is load time for it and other programs. Its Pro(s) is boot time, and not needing to be defragmented. Its Con(s) is its not recommended to be defragmented, as it can reduce its lifespan.