Trolled!? That's a HELL of a haul from two Atheon runs. I did it on hard several times and it took forever for me to get a Mythoclast. I'm not sure why you'd be expecting a Ghally when the exotics don't drop all that much and you could get any of them. There's an extremely low chance you'd get any specific one. I lost track of how many total Atheon runs I did (both normal and hard) but it was probably pushing 25-30 and I probably only got 2 or 3 exotics the whole time (either from that one chest or from Atheon).
Besides, it would be the old one anyway

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So on the Xbox One thread I was asking about people's Crota Raid armor rolls because I'm trying to decide what to upgrade and what to wait on. Then I realized you can just look at random people's bungie.net profiles and see what they have. So I took a sample of people from the Destiny forum.
To summarize:
- Stat type (whether it is Int/Disc/Str or a combination of 2 of them) seems to be pretty randomized and not specific to any particular armor for any particular class.
- There is a definite range on the them, though. Gloves with a base of 100 are pretty good. Chest pieces can go up above 160. Boots are good around 145. I've seen some "bad" rolls as well like 88 on a maxed pair of gloves. These are totals for either a single stat or a combined one (like Int/Disc).
- Also keep an eye on weapon perks on the chest and boots. Chest will have 2 ammo perks (like auto rifle/shotgun) while boots have one. Gloves seem to be standard, though, with the increased speed of special weapon reload and two other perks.
- Only one person out of dozens had a helm, so I don't have any info on that really (it was a Warlock helm with 100 Intellect).
Apparently I made a mistake maxing out my Warlock chest (I just thought it was so cool when I got it). It has auto rifle/shotgun ammo - and I don't really use either. And it maxed at 140 Intellect which is on the low side. But since it was all Intellect that's another reason I did go for it.
So in deciding what to spend your hard-earned radiant shards on, I would go with these overall (max) stat values (gloves: 100-105, chest: 155-160, boots: 140-145), the specific perks (especially on the chest piece which gets two extra ammo perks), and of course the stat build (whether you want more Int than Str, etc). But since it seems like any piece can have any stats, if you get a good one in a stat you like (like a 160 Int chest armor) I'd just go ahead and upgrade that one.