A fun[1] consequence of the all-or-nothing AR-vs-DR thing is how both AR and DR spaces are not evenly populated with all possible values, so the usefulness of an extra AR or DR point is variable.
Consider a Body 6 character with an armoured jacket, for a combined DR of 10. If you look through the book, you'll find (I think, from memory) no weapons that can have AR of exactly 15, even if you put combinations of mods like AR-boosting ammo or bipods and the like. So this character will get no utility out of adding a bike helmet. "I only got Edge because I wore my lucky helmet!" cannot mathematically happen. But a weaker character, with less Body, they might get situations where the helmet is what tips them over the edge. You can play similar games when trading off one armour type against another.
This works in reverse, too. At Close range, the Ares Alpha has an AR of 4, whereas the Colt M23 has 5. The Colt has an advantage, at first glance. But when will it count for anything? Only when the attacker's DV is exactly 9. How often will that happen? Rarely. This pattern is repeated through the tables, both across guns and also when looking at how a gun's AR value changes with range. Small AR changes in the middle of the range might count sometimes. But small changes at the high end or low end? Ignore them. It'll never make any mechanical difference. The Ares Predator's AR is 10/10/8. How often does losing two points of AR at medium range make a difference to you as a shooter? Only when the target's DV is 4/5 (in which case they're not very interesting targets) or 12/13 (which is so high it'll rarely come up; it's troll-in-FBA territory.) In practice, you could make the Predator's stats 10/10/10 and play an entire campaign and it would never make any difference at all.
This has knock-on effects everywhere. For example, APDS ammo will be a lot more useful at a very narrow range of base weapon AR, where the +2 AR it contributes drives you past the breakpoint and means you're getting a lot more Edge than you were without it. In those guns, at those ranges, the -1 DV it also gives you might seem like a reasonable tradeoff. But at other ranges, or with other guns, all its effect will be lost. You should never put APDS in a sniper rifle, for example -- you're already earning Edge because of its high base AR.
In Shadowrun, the cost of wearing heavier armour or switching to fancier ammo is always well understood - in nuyen and in terms of concealability. In 5e, the benefits are also well understood: players quickly grasp that heavier armour = more dice rolled, and more dice rolled almost always has utility. But in 6e, the benefit of trading up to a heavier armour type is variable, depending on your Body and your current armour type, and I think that's very unintuitive.
[1] not fun