The value of an SSD (Solid State Disk) as compared to a spinning platter hard disk is something that can be successfully argued by both sides. However the SANDISK sponsored (no, they did not pay us to post it!) does provide some reasonable numbers you can use as a guide.
The figure they are not including, because it is unmeasurable, is the value of the mental improvement of the user. The SSD is the biggest improvement in computing since the hard disk. In addition to the quantifiable numbers, SSD’s lower users blood pressure and make life better.
This graphic covers performance, power savings, noise, meantime between failure, and more.