Yes its a massive performance boost. ( I don't play games so couldn't care less ), but from a productivity point of view its the single most valuable upgrade our company has made.
Everything just works, Photoshop feels like text file so quickly does it open and save etc, outlook is a dream, chrome is a dream, actually every single program on that ssd is a dream to use now, booting the pc up that 15seconds from power switch to reading the first mail just pure joy.
The difference when switching to SSD is night and day, once you do it you will never be able to go back. I passionately hate using machines without them, now having used SSD's as system drives just for the past few days.
To attach some rough numbers to it, your average high speed 7200rpm disk (WD Caviar Black) achieves about 150 IOPS of throughput on a good day, a 256GB Samsung Evo can run up to about 90,000 IOPS under good conditions and even under average workloads something like 60,000. There isn't a single better upgrade for a non gaming PC.
http://www.pcworld.com/article/2048120/benchmarks-dont-lie-ssd-upgrades-deliver-huge-performance-gains.html
http://www.forbes.com/sites/davealtavilla/2014/03/28/why-solid-state-drives-are-your-best-performance-upgrade-and-why-theyre-getting-cheaper-too/
edit: The games that I have, Dota, Skyrim and simulation games, saw massive improvements, maps loads instantly, games boots in instantly etc etc. Wont get frame rates as its not the SSD's job, but I do get performance increases non the less.