The following videos were created by Dom and Brad of The CRU, and showcase the kind of performance benefits most users see running programs after an SSD upgrade.
MacBook Pro (Late 2011) with a 240GB M500 SSD
I upgraded this MacBook Pro just over a year ago with an SSD and I'm still impressed every time I switch it on. I've done DRAM upgrades on most systems I've owned which always speeds them up a bit but nothing as drastic as installing an SSD.
These two short videos show what a difference it makes to the boot up speed as well as loading basic applications like iPhoto when using an SSD.
Boot up speed
I cloned the data over so the SSD and hard drive are identical, then filmed the Mac booting up with each. Look at the difference it makes!
Again using the identical data on the SSD and hard drive, you can see how much faster applications load in this video.
Lastly, this video shows gains in gaming performance, both on Mac and PC, over a traditional hard drive.