It's up to you. It will always be a risk upgrading to A new version that either isnt out or is newly out.
I've recently upgraded to 5 release candidate and the process was suprisingly easy.
If you want 3TB you've got no choice really.
I'm upgrading my drives in the very near future and I'm going to stick 3TB in all my slots and get rid of my old drives on eBay.