Do you like the red color theme of the Gaming Plus? or the USB 3.1 Ty. C port on the Tomahawk?
Personally, I find the Gaming Plus colors to be garish. I'd go for the Tomahawk.
VRM designs are essentially the same. Maybe Tomahawk tips the scales favorably with a SLIGHTLY more massive heatsink but they should both perform similarly overclocking a 2600...which is to say be very good doing so. That more massive heatsink would only come into play, if it comes into play at all, overclocking an 8 core for long duration encoding or rendering tasks.
Either one will be equally capable for Ryzen 3000, when it arrives. If it matters you could look carefully at the arrangement of PCIe slots to see which might weigh more heavily in your favor. But that's horribly nit-picky, don't you think?