[Closed] Road Frames... "Good" ally Vs "Cheap" Carbon debate...

OK, so we've all heard some of the more mainstream manufacturers wanting to make a few quid chipping in and saying "our premium ally frames are better than a cheap carbon one", but does there seem to be any sort of rule to this?

Cannondale are persisting at least with their high end CAAD10 ally frame, but what tubeset or grade of ally could you actually compare that to from another manufacturer? And at what point does an ally frame become better than a cheap carbon one, or a carbon frame become worse than a high end ally frame?

All largely subjective I know, but I hear a lot of marketing guff, and not much science to back any of it up...

And ultimately, if everything else on the bike was the same (wheels, groupset, components etc.) but the carbon bike (1100g frame) was £1500 and the ally bike (1300g frame iirc) was £1000, the small weight saving aside, how subjectively worth it is the carbon frame (assuming good quality) over the ally?

Opinions please... Or even better, FACTS if you've got them (with a source preferably!) to back an argument up!