I'd say give Endless Legend a shot first since it's a good game that's getting better. Endless Legend does a lot of really interesting things with unique factions with distinct playstyles, varied and interesting sub-factions that provide different units and empire wide bonuses when integrated into your empire, its quest system is so much better than Beyond Earth's it's not even funny, and its combat system will appeal to fans of both Civ IV and Civ V. Stacks of Doom auto-resolve and granular, one unit per tile control on a dynamic battlefield in one solution. The world map is divided up into territories and you can only settle one city in a territory, it's not the standard 4 tiles away. Endless Legend makes the standard thing of settling a new city a new challenge to think about. The tech web is divided into eras. There are so many things that Firaxis should consider straight up lifting.
What you might find off-putting is the military upgrade system. It requires a lot more micro-management of unit types equipment which are tied to expendable resources and have multiple tiers. You get the base version of a unit then create your own version of that unit, which you can name, with different upgraded gear. It's much more busy than Civ V's elegantly simple upgrade system where you pop a unit into your territory, click upgrade and that's it. You have an entirely improved unit. Like you don't have to create a new class, a pikeman just transitions into a lancer once you've researched the appropriate tech and have the right resources. They have a similar upgrade system, with its own screen filling sub-menu to dig through, in Endless Space.
I'd wait to give Beyond Earth a shot until after its 2.0 patch is released. It is better now with the winter update because the trade route system is automated and the wonders are a little more meaningful but the building quest system is still terrible, diplomacy is non-existent, there's no research agreements, no equivalent of the world congress, no faction alliances, Beyond Earth is more basic than Civ V vanilla in so many ways. The affinities take too long to have an interesting affect, health is still too much of a constraint early game (no health resources to pop to counter early expansion) and meaningless late game and minor-powers are annoying because they usually appear where you want to settle a city, they can be over-powered with certain policy choices and there's no political consequences if they get attacked or destroyed. There's no diplomatic action you can take to protect a minor power like you could an important city state, all you can do is declare war. The espionage system is amazing and I hope something similar is populated in mainline Civ games and expansions moving forward but that's about the only thing I'd argue Beyond Earth does well right now.
I haven't played the game in over a month, though. Turn 230-ish was the fastest I could whittle down my win times, so that about wrapped it up for me as far as what I wanted to do in the game. I booted up FTL one day to play that again, and got distracted.