You do end up getting 3 more Princesses from Amazonia, the Amazon unit, and some more experience and Okkarland gives you some Viking troops if you want to play them, but other than that, they're not that big of a deal.
I don't know the price difference, if it's $5 than I guess it is probably worth it, $10 is probably a bit of a stretch.
It also depends if you're tired of playing by the time you get to those islands, if you're tired of playing then it is obviously not worth it, but if you want to play some more then it probably is.
Since I participated in the Early Access (EA) I got the premium version (I think the price was the same - my brother got me the Dark Side EA for my birthday so I actually didn't have to pay for either version).
/C\/C\
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