Thinking of taking the dive....but confused

Sorry for to all you hardcore sigma fans, but the naming of these things are really confusing to someone with no history with Sigma.

I get that at one point there was the DP1, then came the DP1s, then came the DP1x.  And now there is there is the DP1 Merrill?

I ask because Amazon has the DP1x on sale....and I'm thinking of buying it.  I don't need the "latest" in technology, I realize the DP1 Merrill is newer.....I just don't understand what the difference is.  Is the DP1x still the Foevon sensor everyone raves about?  It's still the same wide angle?  I don't get the difference.  Is it just marketing that they are now calling the DP1 Merrill 46 megapixels where as the DP1 is 15X3?

Thank you for trying to clarify this for me!

I'm a 99% landscape shooter and quite excited to try the Sigma out.  I understand the shortcomings and don't give a crap.