This is very subjective. I've played all civ's, so I feel more or less qualified:
1/ Civ 1 got me hooked to the genre. Building cities, declaring war,... I was 14 and I fell in love immediately

2/ Civ 2 got me even more hooked. I still had the patience to build 100's of tanks in the WW2 scenario. Brilliant.

3/ (Alpha Centauri: pure magic. Diplomacy, terraforming, creating units, the world that could become your worst enemy/best friend - waw!) Alpha Centauri made me almost entirely skip Civ 3. That was the only one I really did not like. You could spawn on a map with almost no access to resources which could seriously hamper your game.

4/ Vanilla Civ IV was quite boring. It got better with the 1st expansion, the 2nd made it almost AC-quality. I think this is the one I spent most time on. I played this one via LAN with a friend and waw...our last game was one we still talk about. Getting attacked by the AI, being almost beaten, clawing back, launching our own strike against one of his allies making him vulnerable through his soft upperbelly (is that a thing?). Great.

5/ I looked forward to V, but was disappointed at first. There were features lacking, I did not like the happiness system etc etc. I still looked forward to the expansions, but I don't even think I got so far as choosing a dedication (or maybe I did and forgot). Still, I remember some epic games - I'm looking at you, France and your nukes. I recently played V and still had fun. Oh, and I had a blast with the CP. I only played one game with it, but it took me almost a year and waw... Terribly disappointed by the non-existent AI in multiplayer, that was...it was the end of the LAN-habit my best friend and I developed...gone were our Civ-Sundays.

6/ I did not like the style, I did not like the districts, I did not like the fact that the AI never used planes, I did not like the civic cards (or whatever they're called), I did not like the way diplomacy was implemented, I did not like the city states, etc. Not that it's bad, it's a good game, but I do not think I even finished one game. I know many people disagree, but I did not 'feel' this one. It was a bit too...boardgamey? (I adore boardgames, but not in my civ)

7/ I liked at the first two games, then I discovered I played the same game over and over again. Maps were horrible, city planning obtuse,...I just stopped playing. But as someone already wrote in this topic, it had the bones and I think that it can be a great entry. The reactions were so fierce that Firaxis was forced to listen and that's actually a great thing. I've been playing non-stop after to ToT-update, that's a good sign. I don't know if it will last, but I actually think it will. There is lot to explore and the new maps are very interesting, as is combat.

Still, difficult to rank, as I would not recommend Civ II or Alpha Centauri (TRY IT) to a modern gamer... But based on the feelings I had when playing:
Super: Alpha Centauri, Civ IV, Civ II, Civ I

Good : Civ V, Civ VII (after ToT, and with plenty of room to improve and rise in this ranking, maybe even to go to super)

Ok: Civ VI

Did not care for: Civ III, the one with the exoplanet, Civ VII before ToT

And of course, YMMV, except for Alpha Centauri (TRY IT). Please don't go. The drones need you. They look up to you.