Yeah, unfortunately the price jumped from yesterday. It was a great deal at the time of posting since that was basically a gtx 560 at a $40 savings.
Beyond that, it also provides about 60% more performance than the 550 Ti or 6770.
My advice would be to see if you can find a gtx 460 deal, and then jump on it.
Actually, amazon seems to still have that original deal with the mir:
[ame]http://www.amazon.com/EVGA-SuperClocked-miniHDMI-Graphics-01G-P3-1363-KR/dp/B006KZGGNY/ref=sr_1_7?s=electronics&ie=UTF8&qid=1330618332&sr=1-7[/ame]
Free shipping actually makes it a better deal too than the newegg one. $130 AR. Huge performance gains over the two cards you are considering.
And with that huge performance gain, you will not feel the need to upgrade to sli as quickly. And when new cards are released soon, prices will also drop making the cost of a second card less as well. I would definitely consider that 460 at that price over your other options. Compared to a $120 550 Ti (though the cheapest on newegg currently is $127 shipped, so it is only $3 more AR or $13 more before rebate for 60% more performance), there is no comparison.
Now a quick math lesson, lets be favorable to the 6770 and say the 460 I linked to is 50% faster.
Then, we will have the 6770 at 100% and the 460 at 150%. Now, assuming 90% crossfire scaling, you then have the 6770 crossfire at 100% x 1.9 = 190%. Now, the performance improvement over the 460 is 190/150 = 1.27. So you are talking about 30% performance increase over the 460 I linked to when adding a second card. Yet currently the cheapest 6770 shipped is $118. Given the slight price increase for the 460, it really will increase performance substantially and not require you to upgrade as quickly.