here are some few bugs I read at other micro forum:
1. ballcups pop easily
2. axle pins bend after some use
3. there is a wobble on the tires or they are not perfectly round (something like that)
4. after some abuse, the wheels/rims cracks
Please let us know if you experience some of them. but the good thing is, a losi representative is active on that forum and welcomes all the "bad" feedbacks from mlst owners.