I think the deal with them is, especially looking at Amazon, the actual machine construction is way easier, since there are so many priced around the $350 US mark that have fairly decent print yield sizing. That being said, since the general construction has been so obviously nailed down well, I'm thinking it's up to the engineers to make it something interesting. Think of it like this "we know they're out there, but we made it better by (fill in the blank).
I like what I'm seeing about the SeemeCNC machines, I think they have the right idea, but I've been seriously following Alex's designs here http://carbonoid.jimdo.com/english/products/ but that's because it looks like flat out 3d Printing Porn to me.
Now, I have yet to own a delta, but I do want one, even though my budget prohibits a new, even cheap printer right now.