It depends on your playstyle and who you ask.
I prefer VIT/shield, myself.
Some people say: Level as an AGI build to save pots. I think this only works until about level 85. After that, you start mobbing, and VIT/shield becomes the better choice.
It's probably not a good idea to reset until you're a higher level and single-target leveling gets super slow.
I went from AGI knight to SVD/spear. I use a Hunting Spear with an Archer Skeleton card for Clashing Spiral. With CS, I kill things a lot faster than I ever did with my autoattacks. With 90 VIT and a shield, I tank better too.
I think the most effective way to play a knight (before getting your third job skills) is with VIT, a one-handed sword or spear, shield, Clashing Spiral, and Bowling Bash.
The problem I have with an AGI build is this: To get good ASPD, you need to use either really expensive gear, such as a Heroic Backpack, or AGI/Flee gear, like the Dragon Vest + Dragon Manteau combo, which reduces your defense.
The other problem I have with it is that it's very buff-dependent. Spear Dynamo, Aura Blade, and Two-Hand Quicken require a lot of SP. You'd think an autoattack build would be more SP-efficient, but in my experience, it's the least SP-efficient build. The most SP-efficient build, and maybe the one that's also the least buff-dependent, is Brandish.
I think, in the end, VIT/shield is cheaper and more effective than going AGI after level 85. Getting a Vali's Manteau and a Platinum Shield, combined with your Goibne's Armor, will start you off nicely.
Hunting Spears are cheap weapons, too, and perfect for Bowling Bash and Clashing Spiral. You don't need the Archer Skeleton for it to be effective early on.
Oh, also, Variant Shoes are kind of cheap these days. The price seems to have gone up to 9mil recently, but I got mine for 6-7mil.
I have a pair of Vital Tree Shoes I'd be willing to give you for free. xP
Stats are kind of tricky.
Generally, for VIT builds, I leave AGI at 1, get 90 VIT, and reasonable amounts of STR, INT and DEX.
Leveling spots:
Until 60, do the Orc Warrior bounty board in Geffen.
At 60, do Golems in Comodo.
At 70, harpies and TIs!
I edited this post to remove some stuff. I was trying to cram all of my recent frustrations/experiences into one post, and it didn't work. xP
Edited by LionessLeona, 08 January 2015 - 09:26 PM.