Here is a link on the history of SYNON.
As for how it can help your career, you need to see what your market is looking for. Check out some job posting sites and see how many jobs are looking for SYNON skills. If there are only a few out of a hundred listings then it may not be a good choice. If there were listings in the 25 percent range or higher, I would look into it further. I tend to see a of popular skills out there but jobs requiring those skill in my area are very hard to find. If you are willing to relocate then that can change everything.