I prefer 12. The thing I like the most is the improved snap-to-objects features. If you find yourself doing a lot of node-editing, the improved snap-to-objects features can take some of the effort out of that. In which case, you might consider the upgrade...but be careful, because it will need a lot of RAM, harddisk space, and a good processor speed...if your computer is more than a year old...you might better stay with 8.
If you don't find yourself doing much node editing anyways...probably no need to upgrade (unless you do a lot of design for professional print jobs...in which case it might be good to stay current with software).
My main concern would be could your computer handle it, really. If your computer was made close to the time v.8 came out, probably not.