Same thing with the Armamentarium. He's selling it for the third week in a row, this time with even more Discipline than last week (which was already more than the week before).

I picked that up the first time around, and my Discipline is at 100%. I'm guessing you can't get higher then that, cause well 100%.

Sure, these gloves have +20 to a statistic, but will that matter at all, or are we getting hung up on the number?

It depends on a couple factors:

(1) Your level. The higher your character level, the more discipline you need to maintain that 100%discipline rating. I believe it's something like 230-250 discipline needed at level 30 to have 100% effectiveness.

(2) Your other gear. If your helmet, gauntlets, and boots all give discipline as well, then sure, 5 or 20 extra discipline on your chest piece probably won't make a difference. But, with the wide range of stats your other armor may have in three different categories, that +20 could make a quite noticeable difference in balancing and/or maxing out your stats efficiently.

Same thing with the Armamentarium. He's selling it for the third week in a row, this time with even more Discipline than last week (which was already more than the week before).

Uh, I have that chest from last week, and the one he's selling this week has less discipline. In fact I think it's the same stats as it was from the first week he sold it.

So.....meh?

I bought it last week too and stuck it straight in my vault. Just double-checked and last week's has +131 Discipline and this week's has +136..

That said, while it is at least a little crappy that he's selling the same exact exotic chest piece three weeks in a row and that it has different stats each week, I do agree that it's not worth getting too worked up over.

According to this guy's calculation:
http://www.reddit.com/r/DestinyTheGame/comments/2kx2y5/comparing_armamentariums_and_their_effective/

I bought it and ran a strike. Can't tell much difference between it and my Epitaph. Radar while zoomed is the biggest perk for me, but probably only really useful in PvP.

Spawning with grenades is crazy good, and it even stacks with gift of the sun.

Definitely useful. And I actually did take it into Crucible for a few rounds, to help with my Thorn bounty.

Plus I like voidwalker more so while my Heart of Praxic fire is cool looking it doesn't benefit me.

I have zero problem with Voidwalker (truth be told, it can actually be the more useful of the two because of its heavy damage/AOE approach to all situations, but for what it does, there's gotta be better pro-Voidwalker gear out there...

Also axion bolt is really good i don't know why you are saying its useless.

I didn't say that it was useless, just that spawning one extra bolt does not an Exotic make...
I used it a lot to figure out the quirks and perks, but very rarely got any significant damage out of it unless I was up against a lone Guardian. Void Grenade is much more useful in almost all scenarios...

Was too busy wasting coins on Halloween Cosmetics. Such a hoarder :/