I do not think the vertical foregrip is a plus, I have one, and it is for 1 purpose, the weapon light switch is attached to it, so in the dark, yes I use it, but in normal shooting, daylight etc... I do not use it, I use a very forward grip on the fore end to DRIVE the muzzle where I want it. Yes the vertical foregrip allows you to pull the butt with a lot of tension into your shoulder pocket, but it is not a natural stance. I recommend, trying both under time limits, and let that be your guide. A lot of techniques depend on how much time and energy the shooter is willing to devote to it. A normal person with little time might benefit from the vertical grip technique, but if you are A fast twitch type of person, the forward grip is better. IHMO.
Now, vertical grips that serve a dual purpose, like a grip pod, or a folding grip, can have some advantages, allowing a bipod, and switch built in.
Nothing is perfect.
None the less, whatever you decide, it needs to be learned, and learned well.