I just found it pretty odd - I don't recall ever seeing this situation before where a brand new update on a unit was in the start collecting but not available separately. Boxed games and new edition launch sets sure, they generally have special 'limited edition' sort of units but the start collecting boxes are generally just existing sets smooshed together into an attractive package, generally with a nominal (if any) saving of about 50p... though I remember the Lizardmen set was a pretty good bargain, think you basically got a Carnosaur for free.
Anyway I digress, yes those new Chaos bods are pretty sweet, so much so I have never been more tempted to drift to the dark side, and the new Underworlds group just adds to that! Would love to see some with great weapons...