All are good knives.
RC-4 and highland are sometimes noted as having small handles. However, on the plus of their handles is that they are made of great materials. The Barkie's is beautiful and the RC's handle has a wonderful grip to it even when wet (something the Barkies polished micarta is sometimes criticised for). The F1's handle is something I never really liked and the major factor that prevented me from getting one. I'd have no hesitation in lusting after one of those custom micarta F1's except they have a cost factor to them. Barkies have a pile of handle styles that vary in cost. RC-4 has 3 handle/coating options to it. The F1 can be had in kraton or a much more expensive micarta.
The F1 has the stainless steel factor which a lot of people like and the laminate is supposed to have a toughness that is right up there with carbon steels. The F1 and the Barkie share a lack of choil if you hate choils. Personally, I find I use the choil often on my RC-4 so I like it as a feature.
The F1 and barkie come uncoated, the F1 can be had in either configuration. Choice there is good, what you decide is personal. I like uncoated blades and on my RC-4 I eventually stripped the coating.
All three blades have great sheaths. I love the kydex sheath on the RC-4, but also love the Sharpshooter sheaths that come with the Barkies. I know that the F1 comes with different options for sheaths so this isn't much of a factor.
I guess in the end its just really which little features you like the most. They all differ in subtle ways. Personally, I don't think you will go wrong any way between those choices.