Please correct me if I'm mistaken:
~ The V3 has the updated electronics (display), plus a removable top collar. Plus the swirls.
~ The V4 has the updated electronics (display), minus the removable top collar, and the non swirl body.
~ The V2 has the old outdated electronics (display), the non removable top collar, and the non swirl body.
So, the only logical reason to NOT get the V3,
is you don't want the swirls. Because it is the best
device (operationally wise) of the 4 iterations.
best regards, larry mac