I have owned a KM, and still own what's left of it after around about 7 years of bashing. I haven't had a Rovan but a guy who comes to the NEB bashes has a Rovan and it's been spot on so far.
What exactly is the difference in quality? Is it better alloys or plastics, or did the Rovan fall to bits etc, what exactly makes you say to avoid them? I was considering buying a Rovan item, not a full car though so I'm interested in what specifically puts you off.
And my KM (of old) was one of the first very early models and it has parts that have outlasted genuine hpi items so saying that KM got a bad rap from these early models is slightly wrong, as I recall the early models had decent engines, then KM changed the crankcase to a new design and the engines overnight became garbage fillers, So if they have improved again somewhat since then it has me curious as to what they have changed to set themselves apart from Rovan.
For the record, my km 23 engine is still working fine after all these years, only prob I ever had was a split in the fuel line. And that's some going for an engine IMO.