SSDs do make a huge difference. Because they are built with flash memory, there is no rotational latency when reading files, so they have much better performance than a mechanical hard drive. They also use less power and can handle a lot physical shock (being bumped or dropped) due to lack of mechanical parts. SSDs can be anywhere from 10x to more than 100x faster than a HDD in certain scenarios. Look up Youtube videos of people booting up laptops with SSDs and you'll see
Only takes a few seconds to boot up and some videos show how fast the SSD will open dozens of apps at the same time.