I'm using the EA380 in one of my rigs. It is a Seasonic like the VX, and is a little quieter (which is the main reason it's running that rig). It's rated a little less conservatively than the VX (as the higher models would be), so I don't think the EA500 will be capable of the 500+ watts the VX450 is able to deliver. It is quite possible that the VX450 and the EA500 are indeed very similar or exactly the same supply, with Corsair requesting some additional mods to push the power rating up and then backing off the label to deliver that jaw-dropping difference between label and real-world perf. Reverse marketing strategy, and it worked.
Regardless, I think the Antec is a good choice, but i haven't used it myself so caveat emptor. Corsair may have better support capabilities, I know of a few horror stories with Antec service. The few times I've used Antec, I've not had a problem (knock on wood). It's just that the Corsair has built up a formidable rep and is always the safer choice anyway.
Prime was keeping the Earthenware (sorry, I really can't resist such a wonderful name!) supplies four months ago. You might want to check when they are coming in. They show up as non-stock at IT depot too, so I doubt they are available as of now. Antec does have some supply and stocking issues in India I think. Very erratic availability.