I have grown an arbequina olive tree at my other house. It grew well and made olives.  I think one of the key questions that you need to ask yourself is, why am I growing an olive tree? Some people want table olives.  Think about brining and curing.  Research it first before buying the tree.  Some want oil.  Do you have the equipment to create oil out of olives? Some just want an ornamental tree. Choose your olive variety carefully.   I decided that I wanted to make olive leaf extract, after reading for so many years and from so many independent sites how valuable it is. I am now growing an olive tree for that reason. One site to research would be Oregon Olives, from Amity Oregon.

John S
PDX OR

I grew Arbequina. I'm still growing it. Partly that is about what is most available here.  The guy in Amity recommends Frantoio, but that would involve driving down there on the right day or paying shipping, which isn't cheap.  The more I wait, the more I hear about how great olive leaf extract is, so I plan on making it.  Apparently Frantoio does well here too, if you can get it at the right price. 

John S
PDX OR