How much does it 'actually' actually matter? I have a S912 (MINIX U9) and although I don't have a S905 device to compare with, I don't think you can get any better than that at the moment. With such a big size of a 4K + HD audio movies (for example), you practically/eventually have to store 'em on external storage to stream. Does it really worth having a better video driver and not gigabit? The total experience will be probably even worse?
-San
Well if you are happy with your device and it fills your needs that's fine. we all want to have the most powerful hardware but in linux universe having the most powerful hardware does not necessary translate to superior experience. in this case S912 soc is superior in every aspect but it crippled by its driver. there is no official linux driver for this soc and everything's works with hacks will eventually stop working, user reports several issue like subtitle rendering and so on while using s912's devices in LE. nobody knows the feature if V4L2 and 3d driver release for this devices they become perfect. and if the Gigabit Ethernet is your concern s905D has a Gigabit Ethernet and you can add usb2 Gigabit Ethernet to any s905x devices.