How's it compare to, say, SE4?
It doesn't. SE is all about giving the players enormous piles of options and letting them determine which combination to use for a given match.
ES basically the opposite. Initially you could almost write a single click-for-click match winning walkthrough that worked for every possible match setup. ES has been drastically improved since then, but not so much it's anywhere close to what you'd expect of a 4X. The multiple types of victories are mostly illusory, and though there now tends to be more than 1 way to achieve short term goals they tend not to be meaningfully different.
You might assume this means ES doesn't have an explosive micro problem like, for example, SE does. But you'd only be somewhat right - Because ES is blessed with an Empire Management interface that does a surprisingly great job of not facilitating empire management. Still.. ES' near-mono strategy style of gameplay does sidestep virtually all the explosive micro hell of games like SE.
ES is enormously pretty and stylish, and sounds fantastic. And assuming you don't have a problem with auto-resolving combat, then its combat is just fine too. What it doesn't have is depth of gameplay, meaningful diplomacy, or worthwhile AI.
In other words, there's just one way to play ES: fast expand into total war.
Diplomacy is functionally purely a tool for players to sabotage each other (though I suppose it should be pointed out here that the AI really can fuck human players too).
The AI can most definitely kick your ass, but only because it cheats so obscenely hard while simultaneously playing so fucking terribly, that an AI can easily end up being "fed" to victory by rival AIs.
Depending on how much of a genre player you are, you can probably get 2-10 hours of solid entertainment out of the game - it really does look great, sounds great and has a (mostly) very pleasant interface. But unlike pretty much every other game in the genre, ES has very little replay value. So yeah.. It's just about the exact opposite of a game like SE4.