Board Thread:Game Discussion/@comment-4199297-20130630200721/@comment-4199297-20130706193414

There are generally better things to spend the gems on (for ex. level 3 Training Fields).

Epic Boss Stats lists the reason why 15 is so much harder than 14. And from what I've read the non-plus boss armor is usually not really better than the Big Four, so nice to have, but not something to spend lots of gems on.