It has the benefit of disc tabs too!! It is quite a bit porkier than the Explosif. The tubing seems thicker 853 when you "ping" it. Again, the RM has nice geo. Looks good in this one off colour too.
The Explosif looks the nicer imo BUT I'd go for the Rocky due to it being more versatile with the disc tabs.
If you're definitely set on one of the Kona's, it'd be the Explosif.