Now, people are talking about the new Samsung Chromebook Pro, or holding out for it to be released.
Both chips are similarly clocked ARM cortex cores. The difference is in the GPU. The MT8173 is PowerVR GX6250. The RK3399 is Mali T-860. The fact is the MT8173 is using older tech. As u/ShineChrome mentioned, the size/weight is the bigger deal if you want to use it as a tablet. The SCP is the same size as a wire bound notebook (the paper kind), weighs a full pound less than the R13. SCP also comes with a stylus.
The closest competitor for my money will be the Chromebook Bob, Flip2. It’s the same form factor as the current flip, but comes with the updated RK3399 and USB-C charging. Many people probably won’t use a stylus frequently, but the larger screen sounds attractive. Check YUNDOO Y8 TV BOX here.
Recommended Models, No Regret to Buy:
MECOOL KIII PRO Hybrid DVB TV Box, 2017 Best Featured Model
Mecool M8S PRO L, 2017 Best-selling Model in EU
MECOOL M8S Pro+ TV Box, (Best Seller of Quad-core TV Box)