While I have not owned all of these I have friends that haved owned them so I have been around most
Agama - No exposure
Associated - tried to make it work for 2 years...plastics are very weak and strip easy
Durango - have not seen one up close
Hot Bodies - seemed to get sloppy fast, good ideas behind suspension geometry and adjusments on D812
JQ - no exposure
Kyosho - to expensive and plastics seem to wear out fast for the $$$
Losi - sloppy, 3.0 is fast in the right hands, to hard for the average joe to drive fast
Mugen - current ride. Love it, responds great to changes, lots of steering. My only issue is that the screw hardware seems weak and strips easy
SWORKz - no exposure
Tekno - shock towers are crap metal, to light, can't battle in the corners
XRAY - I like it, new xb8 seems good strong, fast but worried about being outdated by the next revision in 6 months.
IMHO skinny cars became the rage and now it seems that the tracks are getting to rough for them and now manufactures are going back to wider cars to hande tracks and corners better.