by DocCool
I agree that the 4pw tech tile offers most flexibility, also because you can decide when to take the income and therefore don't need to plan for these 4pw already before passing. OTOH the fact that it's an extra action to take the 4pw carries the risk that by the time you took the action, somebody else claimed the power action you wanted.The specialized income tech tiles are better if all you want is ore or coins: the 1ore+1pw tech tile is worth about 7pw (6pw to do a 3pw-to-1o direct conversion), and the 4coin tech tile is worth about 8pw. If we assume that the 4pw tech tile allows us to take a power action every other round (and that these power actions are actually still available when we accumulated enough power), then the advantage of the specialized income tech tiles shrinks significantly to 2pw resp. 1c per two rounds.