So i just bought a vx-5hd 3-15x44 and a vx-3hd 3.5-10. Ill be totally honest ive tried several times before i bought i cant tell much difference between the 3 and 5 both are super clear the 5 might a tad brighter but not much i think thats the 44 to 40 difference honestly. Both show really good detail id stick with hd and just get whatever size and retical over series
VX5/VX6 HD glass is excellent and the coatings brighten the image in the lowest light. I could see to shoot at and beyond legal shooting light.
The 56mm objective gains you nothing really unless you want to shoot at higher magnifications in low light. The 44mm objective gives you a 5mm exit pupil at almost 9x. That will give your eye useable light at 9x right at dark.
The 56mm objective gives you a 5mm exit pupil at a hair over 11x.
Below 9x right at dark, no difference between the two scopes because any exit pupil larger than 5mm is more than your eye can use anyways.
I’d go with the 44mm personally. The 56mm isn’t going to be any brighter at typical magnifications.