I've been using Snagit for more than 10 years and it just keeps improving. I use it for creating instruction materials (and my blog) and it is just essential for me. It's the first software i install on a new computer.
Literally the only drawback is that there's a new and improved version nearly every year and getting the new license & installing the new version beside the old version is a hassle. Hopefully there will be a affordable lifetime license in the future and it will be possible to just upgrade from within Snagit (and replacing the old version because really, you'll only want to use the new version anyway)
I was so excited when I saw the feature that allows easy updates to text or objects in screen captures. I create training materials and information changes regularly. It is nice to have the ability to edit a previous screen capture quickly rather than set-up the scenario again and collect many additional images. I also create software training materials where I don't have a test account - only actual data. This allows me to easily take a screen capture of real information, but edit any names or other sensitive information rather than have blurs all over the screen. It results in a much cleaner look.