I have been using a phenolic tip, however, I saw on the BCA website that at nationals and other BCA sanctioned events, you can't use them to break with anymore. You can still use a jump with a phenolic tip but not to break with. Just a FYI...
Having played with both 314 and z2 would say it depends on your style of play... with the z2 you can get alot more english with less effort, but if you tend to power thru, you may want to stick with the 314