I've been following Nioh in general for a while now but I've never actually picked up a controller and played it...but with Nioh 2 being out now I've been really wanting to get into it - can anyone give me the main points to consider before I dive in?

For starters, Nioh is a Soulsborne game, as you've probably heard. While it is 100% a Soulsborne game, that label is a little misleading, as Nioh is actually quite different from it's more mainline cousins.
For example:

-The game has episodic missions rather than one large, connected world.
-The story is told using standard methods, and is expanded upon in an in-game codex.
-Equipment is handled in a loot-fest manner akin to games like Diablo and Borderlands.
-Stamina management is different, and rewards knowing when to press the attack.
-Much of the post-game revolves around grinding out the perfect build while you go through NG+.
-Weapon movesets are vast, including 3 stances per weapon, with several combos and moves per stance.
-There are skill trees for each weapon type, 1 for magic, 1 for ninjutsu, 1 for core moves, and 1 for your demon moves.
-Guardian spirits, yokai abilities, and yokai shift. (think Devil Trigger from DMC for the shift)

As you can see, Nioh is quite different and this is only the major points. Rest assured, Soulsborne verterans will still recognize the Dark Souls skeleton the game is built around, even as everything else is different. If your interested, I highly recommend the game.

A few quick tips:

-Nioh has a steep learning curve, but if you take the time to git gud the gameplay will come naturally to you.
-The Dojo missions help a lot with the learning curve. Especially the Training Grounds, where you can spawn enemies at will. Use them.
-It's probably a good idea to focus on one weapon type until you understand the core mechanics of the game. Then branch out if you want to.
-Don't worry too much about gear stats at the start of the game. Just worry about the level of the gear and, in the case of armor, what weight category it is in.
-Once you've gotten a good handle on the game, look up a smithing guide so you can start making your own gear.