You'd be hardpressed to go wrong with any of those, though I'd definitely rank the Thermaltake unit last.
I have an EVGA 1300G2 and a few Seasonic X1000s and I've been happy with both of them. The hybrid fan mode on the Seasonic is nice, but how much that is worth will depend on they idle noise of your system already. With price no object I'd probably take the SS over the EVGA, for slightly better parts and the fan mode.
Overall, the AX1200i has a reputation of being a little better than the Seasonic, but you'd be hardpressed to find much of a difference between them other than the CorsairLink support. If you'd appreciate that, go that way. I found the CorsairLink software to be a bit of an abomination when I used it for an H80i, but that's just me.