from what i have seen at the tracks i race at the losi sct hasnt showed much.durning the summer out door racing season only two showed up and they didnt produce and for the indoor winter season there hasnt been any losi's raced at all, i personaly race a traxxas slash and i am very happy with it so if your looking at sc trucks to buy check out the traxxas slash,associated sc10,or the blitz by hpi those seem to be the three top choices at the tracks and each do very well racing in the sc class.now in other parts of the country the losi might do pretty well at their tracks,i can only tell you what i have seen.
I originally raced the Slash and when the Losi came out, thought I HAD to have one and was impressed with the mid engine but it now sits on the shelf and I still race the Slash. Also have tried the SC10 and still like my Slash. The only one I am not familiure with is the HPI but you might want to see who runs what at your local track. The more recers that run your chassis, the better chance you will get help with any problems at the track.