I keep leaning towards 'Age of Wonders Plantefall' but read so many negative comments about it that it keeps putting me off.
It's not my personal cup of tea, but I definitely don't think it's a bad game. My main critiques of Planetfall are that it's too heavily focused on war and the tactical battles (the latter start to feel repetitive after a while); and that the empire-management side is (at times) overly-complex to hide its lack of depth. That's just my own take, however.
Truth be told (to play devil's advocate), Planetfall does a lot of things well: Diverse factions/races, pretty cool unit rosters for each, the in-game "mods" allow for wide variation in how you spec your units, interesting lore, a high degree of replayability, nice visuals & art style, the excellent tactical combat system (even if it's over-used), solid production values, and a high degree of polish that has left relatively few bugs.
Bear in mind, too, that Planetfall has solid scores amongst both players and "professional" reviewers, and has clearly sold at least reasonably well (else Triumph wouldn't have continued to make DLC for it, regardless of Paradox's business model), so it must be doing *something* right. Whether those "something's" are what you're looking for in a 4x/strategy game, however, largely depends on what appeals to you.