Both the Ti and non-Ti version are good cards. For a couple dollars extra, maybe $20-30, the Ti is probably a better investment, and for a couple bucks more than that one of the dual fan non-reference design models is an even better buy as it will run cooler and quieter. I would suggest something like this if you can swing it...
It won't do much good to buy one really expensive card and one cheap card in SLI since one won't keep up with the other, so you'd be better off with just a matching card to what you've already purchased.
If you've already purchased the EVGA card then go with it, it's a good card, it's just not the amongst the best ones.
No worries, your PSU is rated fine for SLI with two GTX 560's. People around here are just a bit upitty about their PSU vendors and think that only three companies are capable of making one that works. If yours dies (not likely) then go with their recomendation. If not, no worries.
EDIT: I can eat my own words. It only has 2 x 6-pin PCIe connectors, which means you'd have to run the second card off of molex power connectors which isn't the end of the world, but it's not ideal.
If the PSU dies it's very possible that it can take other componets with it when it does.
I'll agree that the review doesn't paint a pretty picture, but that's what VRM's and multi-phase power are for. As for it dying and taking out other components...ever had that happen to you, or is it just something you've read can happen? I've had 3-4 no namers go on me without any collateral damage and most friends I've had with dead PSU's have the same story.