I have not used either products mentioned, primarily because they're not free and Camtasia would be over my budget.
However, I do use and can suggest a free and open-source alternate. It's called Open Broadcaster Software, OBS for short. It is very flexible and easy to use, with a little configuration. You can screen-capture or live stream to other services (ie. Youtube and Twitch.tv). Updates are regularly delivered via it's built-in Updater and upgrades run smoothly. View their changelog page, here. Plugins are also available, see them here. It's available in both 32-bit and 64-bit flavours for the Windows OS.
I had the chance to use Camtasia and liked it more than FastStone. I do not have the license though so am using what I have I'll also checkout OBS. Thanks Huracan