Bought my 550 just about a year ago, no issues to date. Most of the problems on here are from the earlier models that were Hisun machines, not from those that bought more recently when they switched to Linhai.
I've had my T-boss 410 since 2020. No problems yet aside from some adjustment issues. I don't use it much, and the battery leaves something to be desired. It needs a replacement is all.
Cue Joe Breaux.....😎