Reasons for choosing 3.x over 4.x?
 

So i just got a vbulletin license and i'm going to convert over my existing phpbb forum. I have the ability to download both 3.8.x and 4.x and although i really want to install 4.x because it's the latest version i figured i would ask the community about it first. I would like to hear some of your reasoning as to why i should install 3.8 and stock with the 3.x tree over going to the new 4.x versions.

My site will be a online community with articles, blogs, a store, etc. btw, I didnt purchase the suite version so no need to compare those features.