Difference in JTS from Vivid Solution and locationtech

They are the same project JTS moved to Location Tech on Nov 3, 2016. AFAIK (and looking at the github repo) there has not yet been a released version from the LocationTech branch.

So you should probably continue to use the Vivid Solution's release until a new version comes out, unless you have to be on the bleeding edge.

UPDATE 12/2018

There is now a JTS 1.15 release from the Location Tech version of the project. Follow this upgrade guide for details of how to make the changeover.

The com.vividsolutions packages are used in older versions of JTS. JTS has now migrated to being part of the Eclipse LocationTech working group, and so the package names have been changed to reflect this. New releases will be made under this package name.