Challenge missions and factions

I have made it substantially further in the game since my "newbie mesmer needs help" thread, however I still have some "newbie" type questions.

I've collected the spear and the chest that I will be using to fight Shiro, and in doing so, have run across the Kurzick's and Luxon's. I have 500 or so points towards the Kurzick faction but am not sure how I got them, as I don't have any Luxon points and I did the same thing in both areas, that is simply completing the quest in the area. So, how do you gain faction points with the different factions?

Also, are the challenge missions involved with gaining the faction points, and if not, what is the benefit of completing them?

You do gain faction from quests and the challenge missions as welll. 1k Luxon/Kurzick faction can be traded for amber/jade respectively. Then you can sell that to the rare material trader.

The "Befriending" quests need 10k faction to complete so don't rush off and spend your faction yet. Collect the 10k for one side, say the Kurzicks, by doing Kurzick quests (the rewards are listed in the Quest Log) around House Zu Heltzer, competing in Alliance Battles, etc. Talk to the quest reward person to complete the quest then you can trade the faction for amber, finishing the quest doesn't cost any faction you just have to have accumulated it.

If desired you can then start collecting Luxon Faction and do their "Befriending" quest for 10k Luxon faction, trade it in for jade, etc.

You cannot have more than 10k faction so hold off on collecting quest rewards that put you above it until you finish the befriending quest and cash some in.

Note that there are repeatable quests available to help you gain faction, as well as one-time quests, so just questing will get you there.

Faction is per account so collecting it with more than one toon adds to the account's total.

In order to deal with NPCs of one side you must have more of their faction than the other, so it is better to finish off one side then go back and do the other if desired. Also, cahsing in one side's faction causes you to lose a like amount from the other. So if you have 3000 Kurzick and 1000 Luxon and trade in 1000 Kurzick you will end up with 2000 Kurzick and 0 Luxon.

So there is nothing that enhances the story or plot by siding with a faction then, and the benefit is simply in gaining faction points, which you can then trade for items that you in turn trade for $$$? Seems kind of anti climactic.

Umm, one thing, after ya collect the spear and "chest", ya have to go back to the city and do Sunjiang District (mission). THEN you can do the befriend quests and get deeper into the both factions territories.....