Sigma 530 super vs. Canon 430EXII

I asked this question before, but not in the same form.
Is there a good reason to select one or the other of these two options, other than cost? I have an XS, but I may get the 50D in the future as an upgrade.
I don't expect to do remote dual flash, but I am concerned about reliability and flash accuracy.
Is the Canon worth the extra money compared to the Sigma? After carefully looking at specs, I can see some advantages to the Sigma.
What do you recommend?

Hi, I went through the same dilemma last week and ended up purchasing the canon for a couple of reasons:

1)Build- feels much sturdier than the sigma/probably more reliable
2)Future compatibility- If canon updates ettl sigma might not work....
3)Focusing- Canon has a nine point focusing system vs one for sigma

That being said the one feature I do wish the 430ex II had is the ability to function as a master. If you ever decide use more than one flash you have to get the 530 or something comparable to use as a master.

I have the Sigma 530DG Super Flash, and I have a few problems with it. It isn't 100% reliable, in fact it isn't even 75% reliable. I suspect my particular unit is a bit defective (ebay purchase) but I do like the results when it does work.

I would go Canon.

I use 2 of the sigmas and they are flawless. I've bounced them off a couple tile floors on accident, zero trouble with them.

I expect to make a decision within 2 or 3 weeks - the Canon rebates expire on Jan. 15. If it is the Canon, I'd want to hit the enter key before then.
Thanks for the input.

Sigma 530 Super

Pros:

1) more power
2) can operate as Canon proprietary "Master" or "Slave"
3) can operate as an optical slave flash with any flash

Cons:

1) Doesn't communicate with Canon Digic III or Digic IV in-camera flash menu
2) Sigma manual and flash menu are near useless