I don't own that particular Enermax, but I own the 420 watt version. It's been solid for me. Kudos to you for wanting to invest in a good power supply. If I had it to do over again, I would have gone with one of the Seasonic Super Tornados or their new S12 series. The Seasonics are quieter than just about anything else that has a fan in it, so that would be my choice. My Enermax isn't super loud, but I want as little noise as possible. Seasonics are made with compents that are just as good as the Enermax I have, but again, their units are quieter. Give Seasonic a look if noise is important to you.
Oh, I didn't see the SLI part. I kind of find it hard to believe that SLI is going to catch on due the the cost, so I ruled that out imediately when I decided to build my new computer.
Edit: I originally read your post quickly and thought you were talking about the OCZ Modstream. Do a search on the Ultra-X-connects. I've heard bad things about them, such as failing and stiff cabling. Between those two, Enermax is the clear choice.