The benefits of using an SSD over a conventional HDD are huge; they offer higher read and write speeds, smaller form factor than desktop HDD’s, much faster access times, and the lack of heat and noise production.
Read and writes are higher than an HDD simply due to the fact they use flash NAND memory. An HDD is limited by the speed it can spin at, and the faster they spin, the more noise and heat is produced. SSD’s usually offer between up to 512MB/s read (limited by SATA 2), and 70MB/s to 512MB/s writes (limited by SATA 2), giving them great performance when opening large programs.
Currently, most consumer SSD’s come in the 2.5″ form factor, making them smaller than 3.5″ HDD, allowing several drives to fit in the same slot. OCZ Colossus is a 3.5″ SSD which uses a raid controller within the 3.5″ case to make the SSD around twice as fast for sustained reads and writes.
Access times are virtually nothing, <0.2ms. Compared to a Raptor's 7.4ms or a regular 3.5" 7200rpm HDD's 12ms+, this is exceptional, and makes them brilliant for an operating system.
SSD's produce absolutely no noise, which is a clear advantage over HDD's, and a godsend in "silent" PC's. They also produce little to no heat, which means they can operate in PC cases without any airflow.
These are ideal for games, levels and maps will load incredibly quickly compared to standard hard drives.