Vinh and Mike are both standup guys.
Vihn's light I would expect to out throw mikes light for a while at least.
Vinh is gunning for balls to the wall max output...heat be damned, etc. IE: Vinh is making a specialized monster that gives its all...at the expense of heat and run time.
I have a LOT of vinh's lights...and when I want to slam the photons its my weapon of choice.
Vinh doesn't just up the amps and dedome...he's binding to giant cu sinks, adding solder to max out ground paths, etc, reinforcing switches and connections, etc...to make the lights do as much as possible.
Mikes Tn31mb is similar except that he makes the tint warmer which costs lumens/lux...and he limits the drive to amps that can run about at more stockish runtimes and heat generation.
So, they are making lights that are superficially similar....but functionally different.
We simply choose the version that makes sense to us.....which of course for many of us means getting both.