I love FreeOrion, it's awesome! There's so many interesting technologies, ships, game mechanics, etc.
The idea of minimum turn requirements for construction and research and the multiple simultaneous construction/research projects that come from it add a fun strategic layer. They also seem to add a lot of very interesting balance options, like certain defensive choices being relatively cheap but requiring a relatively long time to research/build.
The same is true for the newly introduced policies feature, where some of them grow stronger over x rounds which means you can't switch back and fourth without a severe penalty. Yet at the same time you aren't artificially locked into certain options like some other games do.