Grey Knights, so much in one little box

So I snagged a box of Grey Knights to day, and I didn't realize that box can be build 4 different ways. I find myself torn between the Purifier squad and the Interceptor squad. Does anyone who has played or played against Knights in the past have any advice?

Are you using them for allies or for your army list?

I love the basic strike squad guys.

purifiers are pretty nasty. they're able to be played as a strong hitting melee force to pretty good success. i havent seen interceptors used yet, but what i've heard online is mixed reviews.

You're basically win/win.

As Robyn said, your basic strike squad is a really good, all around unit, more than capable of taking on most other units.

Interceptor are likewise and more mobile. Warp Quake is also great for disrupting the other dudes deepstrikes.

Purgators are OK and can be nasty, but are likely the red-headed stepchild here.

Purifiers are Strike squad +5. With the 5 in the box, you can take 2 PsyC, and upgrade the individuals as you see fit.

Either way (allies or new army) I'd lean toward the Strike Squad. They're good all around, can hold objectives and are cheaper than all the other options. Grab a brother captain or brotherhood champ and you're set for allies.

So far I was going to go for Termies to fill the troop slot for allies (giving me time to build into a full fledged army), and I was going to use a Dread as a stand in for the Throne of Judgement until such a time as I get a real HQ. On the note of HQs, I have noticed that WH Fantasy Clerics could very easily be moded into Inquisitors in Power Armor or the like.

Between a stand-in chair, Termies, some form of Knight squad, and a Tech Priest that I am eyeing up, I can see myself having 1k points of GK in a hurry, with a pair of Orbital Strikes at my disposal, as well.