Looking at it on the website, it looks like a decent improvement on the original. I doesn't look like enough of a change to get rid of an older one, but if you're buying your first, I'd go for the new one.
I have been using the lathe with PSI's 2 piece kit. I do have 2 other presses but favor the lathe kit. To answer your question about upgrading. Only if you're not satisfied with what you are currently using