I've been playing DS2: SOTFS
It's the weakest of the 3 imo (since it doesn't have the amazing world design of DS1 or the level of boss fights in DS3), but I'm having a ton of fun anyway. I think one of the biggest things that turned people off from it was the game gives no indication at all how important agility is, or even what it is doing, so unless you look up detailed testing players did you can't build a reasonable character.
I like how different the game is. All 3 are quite different, which makes them all worth playing. DS2 is the slowest and most methodical, there are many places where you will be killed almost instantly if you rush in. Bonfire ascetics are a nice feature. Some bosses are up there with the best
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Fume Knight and Ivory King
Magic is probably the best of the series. I never used much magic in the others, but this time spells give you more options. There are the basic damage dealing projectiles, as well as AOE, but there are also defensive spells of various ranges (Focus Souls is a fun one to put up when something is charging at you), spells intended to stun rather than damage (Soul Vortex is great at this), the greatsword spells for wider hits and going through obstacles, etc. This is the first time I've really liked a mage character as much as melee.