Best value for money ssd at 120 or 240 gb ?

Honestly the 240 gb is better. I would buy the 480-512 gb size myself, because I have both the 120 and 240 gb sized SSD's and the 120 is very hard to use as a primary HD, if you are only using it on a Windows base PC. With that said, if you have a bigger spinning HD for your data, the 120 gb will work as a boot/OS drive and not too much more than that. The whole idea (to me) of using an SSD is to get quick boot/load times as possible. So with that in mind, I try to get the biggest SSD that I can afford, so I can put all of my most needed/used games/apps on it and enjoy the quick load/boot times of the games/apps.