both plugs are ps2 using the keyboard as we speak, im currently using it through a proper usb adapter for my macbook. The trackball is fairly low down so there is not much chance to move it, it is slightly juddery compared to my mouse but then it is running through a usb adapter together with the keyboard and it probably has really old tech running through it.
The only thing is i wish it has one or two more button so i could use it to scroll a page or have a scroll wheel.
I'm not to bothered by the fn key placement as im used to laptops and space savers so i can adapt. But again you will have to relearn the keyboard and that is often the most off putting thing about space saver keyboards with their non-standard layouts. I still hate the placements of home and end keys but i'll get used to them again. The euro layout is much more important for me anyway