What 1TB SSD costs $400? The 512GB SSD I bought merely cost me $120. The 1TB Model costs a slightly more than twice that.

So far I've been completly disappointed with my purchase. Compared to my 3TB HDD I've spent more money yet only see a 2x improvement in speed compared to my HDD for sequential loads. Sure it now boots much faster but that's hardly worth the money I've spent on it.

I was just about to say I've never seen 1TB SSD's anywhere near that cheap - Apple in Australia still charges $800 to add a 1TB SSD to a MacBook Pro. But I see Amazon now sells SanDisk X400 1TB SSDs for $230 USD.

Alas, everyone still seems to recommend Samsung Evo if you want reliability (I do), and $330 for a 1TB EVO 850 is still a little more than I want to pay. (Especially when a 2TB spinning disk selling for $95 now.)

I'll keep the iMac until it gives up the ghost completely, so resale value isn't a parameter. It's more a question of "will the $400 give it enough longer life to make more sense than buying a new one now".

Perhaps I should go with a 500GB SSD and transfer the movies and whatever else is taking up space to the server. And then buy a new iMac once they put the next-gen GPUs in them.

Why not a hundred dollar ssd and a drive upgrade kit for $50, so you can keep your current drive as well? Or fit a new 3TB drive while you're at it.