Based on TCGPlayer.com API, here is the distribution of individual card resale prices for Evolving Skies and Fusion Strike sets:

Based on this and the empirical pulls from booster packs, the $ value of each booster pack in a booster box can be calculated:

Individually Pokemon booster packs sell for $3-4, but the median actual worth of cards in the booster packs is $1-2. However, if you pull a rare card such an alternate art, the actual value of the booster pack could be as much as ~$50. So pulling just one booster pack with a good alternate art can easily recover half the cost of a booster box of 36 booster packs (~$90-100).

In my case, I found the actual value of my Evolving Skies booster box based on empirical pulls was ~$110 whereas Fusion Strike booster box was $51. This indicates that, of the current sets, Evolving Skies can be a great investment, if on sale.