When I'm looking for a new mech, here's my crash test:
- diameter: must be 22mm (not 23, not 21.8 or other funky size)
- switch: must be bottom and recessed, very short throw, not wobbly, no misfires, not too stiff
- nothing telescopic to adjust (I prefer topcapless mods, or hybrid adapters at least)
- available in 1 single piece 18650 tube, and as short as possible (less than 80mm)
- as much sleek and flush as possible: no logo, no slant, no bevel, no engravings, no serials
When a mod has passed this test, I'm ready to try it and consider minor details such as availability, finish, material, conductivity, venting, price, etc.
Of course that's just personal preference coming other time after using a lot of mods.
If this is your first mech, the classic Nemesis is a good place to start.