Maybe a bit late to the posts, but my wife and I bought OM-1 bodies last November and have been using them extensively, mostly with birds.
All I can say is, that it's simply an amazing tool for bird photography. While I have read mixed reviews of the bird detection and tracking, our standard settings use them with ALL area AF points and it does a very fine job finding, tracking successfully, even against mixed backgrounds.
Of course, it is not perfect, but it is simply the best camera we have used to date.
We love the ability to customise four custom modes.
My only gripe is that I would want the MENU button in the bottom right near the PLAY button for less cumbersome access, but it's not a biggie.
I am glad we ditched our heavy Canon gear 3 years ago, but realistically the OM-D E-M1X were just OK for us, not quite up to the Canon 1DxMkII in our views. Glad Olympus upped the game and developed the OM-1, it really is a game changer.
Cheers guys