Deus Ex original, especially when modded, is a great addition to any library. These were the days where games were games and didn't hold your hand. One of the best titles out there and one that actually hit history exactly on. Warren Specter said he could not remake this game today because of how accurate it was to real world events.
Deus Ex invisible War, while dumbed down from the original, is OK enough to finish to completion. The idea was to take the Deus Ex formula and bring it to consoles. Mostly a fail, but not terrible either.
Deas Ex Human Revolution. Another gem. Arguably the 2nd best game in the series. Massively improved visuals with great game mechanics. The story again is top notch and should not be missed and introduces us to Jensen. He has a lot of tricks up his sleve and can be outfitted for combat, stealth, or any number of ways that suits your play style. Great game all around.
Deus Ex Mankind Divided is the last of the series and a mixed bag due to some design choices. Where it fails vs the others is you are pretty much stuck in a single location where the others had you running all over the world. While the single location is pretty detailed, it doesn't bring that where am I going next mentality. It also attempts to introduce the concept of racism into the series and fails, but you probably already figured that out from the title. They use the Semi-woke mentality to block you from locations in the game to impede progress. Good enough to again finish, but lacks the soul of the others in the series.
Rank:
1. Deus Ex, especially modded.
2. Deus Ex Human Revolution (Very close 2nd)
3. Deus Ex Mankind divided (distant 3rd)
4. Deus Ex Invisible War (Really distant 4th)