Been though quite a few mech clones using trial and error. Most, but not all, bought from Fast Tech. My opinions:
Bolt clone: Performed great for a while then the switch went out. Gave it to a buddy to use for parts.
K100: Zero complaints. Gave it to my wife and she loves it.
TVS: Heavy and durable. Worked pretty well. Gave it away after I discovered the best clone in my opinion
Sentinel V3: Performed ok I guess. Never really cared for it and gave it away.
Sentinel M16: Heavy, durable, worked well. Gave it away (see TVS)
King: I have had 2, a brass from FT and a stainless from HCigar. Looks great and performs well. Finicky with batts and toppers. Frequent adjustments needed. In my opinion a design issue which also plagues the Chi You.
Launcher V2: Durable and great performer. Still have it and use it solely as a dripper.
Maraxus: Very durable and great performer. Still have it and use it solely as a dripper:
HCigar Nemesis with magnet upgrade: The best clone in my opinion Other than the Launcher and Maraxus I previously mentioned I use no more clones anbd don't plan on buying anymore.
Hope something I wrote was helpful in some way.