The master branch worked without issue for me on ubuntu 15.04 and 15.10. I had to install clang-3.6 and libclang3.6-dev, if that helps.
I don't actually use the program on a daily basis, but I do pull it out on special occasions. Most recently I used it while tracking down https://github.com/atom/electron/issues/3380. It's helpful because Electron/Chromium is big and I'm unfamiliar with the code.
All in all this is not as feature complete as source navigator, which is old but works for me better still.