I have a set of each for me and my brother. It comes down to one simple statement; the Slash is a toy, the SC10 is a racecar. It all comes down to what you want out of it. The Slash is good for budget racing/playing, but is heavy and has considerable chassis and suspension flex. It is slower to react so it tends to be easier to drive initially. The SC10 has precision handling and lap after lap consistency along with a world championship winning lineage. It does give up a little to the Slash in the durability department, but I have broken very few parts on mine and it's had a rough life so far.
If I had to pick one its the SC10 hands down.
If I had to pick one its the SC10 hands down.