I’ve written of this elsewhere before; I have an xG3v2 in each knife edge (P5).
Mine are kinda deep…
The lifting is eh (can do bottlecaps, thats about it)
The sensing of fields is okay (microwaves, laptop bricks are fun to mess with)
The ‘sensing’ of pinching with another strong magnet, though… 
Lots of ‘play’ opportunities… I’m getting more of these