Yes, it is, but you have to look at the combined your stats closely before doing it to see if it will have a real benefit or not. I'll explain. You're going to get 2 additional points in each stat category for each masterworked piece of armor, so ideally you want to make sure that those two points take you over the threshold into a new level for your stat categories. For example, if my current stats for all my armor (all un-masterworked) combined add up to: 48 Mobility 23 Resilience 59 Recovery 58 Discipline 66 Intellect 44 Strength Then if I masterwork one piece (say a helmet), my new stats are: 50 Mobility 25 Resilience 61 Recovery 60 Discipline 68 Intellect 46 Strength I have now gained three actually useful overall stat levels (in Mobility, Recovery, Discipline) by this one masterworked armor piece but the rest gained no benefit. This is because you only get the benefits from a new tier in stats after you pass the ten-point threshold. For example, if your overall Mobility had been 40, you would have exactly the same level of Mobility at 49, so those 9 extra points are wasted until you go over 50, which is what you are trying to do by masterworking armor. You don't want to add 2 points in each category and have them mean nothing for the cost of precious upgrade materials. So to continue, if you masterwork a second piece of armor, you would now get these stats: 52 Mobility 27 Resilience 63 Recovery 62 Discipline 70 Intellect 48 Strength This second masterworked piece of armor only gave an increased overall stat benefit to Intellect, the rest gain nothing but do move closer to the next threshold. Now let's do a third piece, giving these stats: 54 Mobility 29 Resilience 65 Recovery 64 Discipline 72 Intellect 50 Strength As you can see, a third piece of masterworked armor would give you a new level of Strength. A fourth upgrade would give one more level of Resilience: 56 Mobility 31 Resilience 67 Recovery 66 Discipline 74 Intellect 52 Strength But a fifth piece of masterworked armor will give you no immediate benefit 58 Mobility 32 Resilience 69 Recovery 68 Discipline 76 Intellect 54 Strength This doesn't mean you it's a total waste of time because if you swap out pieces of armor, like we sometimes do, you might now end up over the threshold of a stat category. Of course you might end up dropping one too. So masterworking is best done once you've decided on a near final loadout or build. But overall it is worth it is you are aware of the way stat levels actually work. Cheers.

If you get a damn good roll with an exotic you like? Might as well Masterwork it.

Absolutely. Not so much for stats IMO, but for the mods. Another opinion I have is not to MW anything that doesn’t have a 1410 level max.

Depends on how much you use armor mods like Charged with Light alongside other mods, and if the +2 points per stat per armor piece makes a difference in your build.