The general consensus is that getting to 950 is worth it. Fully unlocking Argus missions requires completing all outdoor quest content, and then completing a series of mission-related quests from Alleria in Mac'Aree (to get to ilvl 925) and Turalyon in Antoran Wastes (ilvl 950). Note that the Vindicaar must be in the correct position to accept these quests.
Argus missions spawn more frequently and expire in the same time frame: 6 hours.
Argus includes missions for Blood of Sargeras which allow alts to become reasonably self-sustaining. The net profit (assuming bonus loot is acquired) is always 3 bloods (600 resources) regardless of ilvl.
Don't worry too much about equipment until you've unlocked Lightforged (epic) equipment by completing
阻截军团的战争机器 for Turalyon. In fact, I've been stockpiling my
阿古斯装备箱 on my alts until I complete the quest, as the gear is generated upon opening.