I had Nikon AF 300mm f4 at the time purchased X-E1. It was tough to focus using viewfinder, and almost impossible when using screen handheld. So just sold that glass as well as other Nikon stuff.
X-E2 and X-E2s have lower magnification mode in the viewfinder comparing to X-E1, and it makes focusing with all lens noticeably easier for me. I've realized that price went dramatically down for Nikon AF glass, and just purchased AF 300mm again almost two times cheaper then sold it in 2013.
Here's one of the result from this lens on X-E2s. I've purchased lens for bird shooting, but didn't catch nice bird yet : )