I really would like to order this Viking CF from Amazon, and judging by the wording of the rebate the Tigerdirect.com one should work. However, the big red flag to me is this: if this rebate is good at Amazon too, then why doesn't Amazon update their rebate information with the $20 rebate instead of the $10 one? I'm sure they'd sell a lot more of this item if they did that.
The fact Amazon doesn't update their rebate to the better one tells me either: (1) the better rebate does not apply to Amazon or (2) they are lazy about updating their pages. I don't feel like gambling over $20, so I'm not willing to risk the reason may be (1).
I recall that Kensington said a perfectly valid rebate of theirs (where the purchase complied with all the terms listed) would be invalid because it was not intended to be used with their "sale" price. Fortunately I found it out before it shipped, so I was able to cancel, but the point is companies can "invent reasons out of thin air" to invalidate rebates if they want to. I have no experience with Viking, so I can't make an assessment if they are nice or hard-nosed.
If I had a printout of Amazon pages showing a $20 rebate (instead of $10) and then Viking denied it, I'd feel reasonably confident Amazon would do something to make it right, but when only $10 is listed if I then sent in the $20 rebate and it was denied I don't think I'd have a leg to stand on. So I guess I will sit this one out unless Amazon updates their rebates.