Sli'ing vs buying a new card

[Spydir]

So still kind of building a system. Here's my question. i've already got a:
EVGA 01G-P3-1556-KR GeForce GTX 550 Ti (Fermi) FPB 1GB 192-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card
on my new build i'm looking at getting :
MSI N660 Ti PE 2GD5/OC GeForce GTX 660 Ti 2GB 192-bit GDDR5 PCI Express 3.0 x16 HDCP Ready SLI Support Video Card

So i've never sli'd before and i'm curious, if I purchase another of the gtx 550 would it be at least equal to or better than the 660? If it is equal or better than i'd be saving about 200 bucks off the build, and thats an appealing idea. Thoughts?

 

[Deemo13]

The GTX550Ti SLI would be lesser than a 660Ti in performance. Not to say it would not be a decent setup. The 550Ti is old, but it still gets the job done, and there is no reason to get rid of it.

There are a few downsides to SLI. One of those is microstuttering. Also power is a factor.

 

[Spydir]

Best answer selected by Spydir.