People often ask me whether they should purchase V neck or crewneck T-shirts, as if one is clearly superior to the other.
In all honesty, my answer to this question has changed again and again. Five years ago, I was all in on V neck T-shirts. They simply looked better, no doubt about it. You ask me that same question today and I'll probably switch my answer over to crewneck, unfortunately without a good reason as to why.
Just like anything in fashion, perspectives change, and there are times when crewneck shirts are "in," and times when V neck shirts are "in." I think right now, we might have landed on a time where crewneck T-shirts are more popular.
This being said, I believe that you should absolutely own both V neck and crewneck T-shirts at any given time. First off, neither will ever go out of style, since they're such staples in any man's wardrobe. I just ask that you keep your V necks at a more conservative depth - deep Vs can look ridiculous.
Secondly, both serve distinct purposes. For instance, crewneck T shirts look better with crewneck sweaters. V neck T shirts can work better with dress shirts. Etc. etc. etc.
So the next time you're choosing between crewneck and V neck, just know you'll likely end up having to get both in your wardrobe, so just flip a coin.... I say that half jokingly.