The new Subversion 1.8 features look quite good for a centralized Version Control System (VCS).

But note that the Subversion 1.8 working copy format is backwards-incompatible. Some tools like recent TortoiseSVN versions will use the 1.8 format by default which will cause compatibility problems for IntelliJ and any other tools that do not yet support it.

So for now, it is probably better to stick with 1.7 and wait until all your tools fully support 1.8. For IntelliJ you might want to watch [IDEA-94942] for status updates.

Personally, I am more interested in Git anyway because it offers all the flexibility of a decentralized VCS. I am reading the free “Pro Git” ebook on my Kobo eReader (epub format).