I like what they've done with the Followers. Well, at least with Lyndon (the Scoundrel), who's the only one I've tried so far.
I'm running a Demon Hunter, and people were saying that using the Follower with the same mainstat should be the way to go now. I like that, because I tried all three followers a few different ways back when I was first starting with D3, and ended up just going with Kormac for every character. He's an extra meat shield, plus he heals and helps with resource regeneration. Lyndon has the best smart-ass remarks, and Eirena is cute and I'm usually fine with a cute blonde hanging around, but when it's life or death, you can't really mess around.
I figured they wouldn't change the look in-game when you equip them with different armor and stuff, but was pleasantly surprised that you see them wielding the weapon you give them. Lyndon has a Windforce, and it not only appears in-game but also knocks monsters back. Angelina found a Demon Machine (shoots explosive bolts) and when she outgrew it, she gave it to Lyndon, and he was shooting explosive bolts for a while, and they were actually killing things, too. Very cool!
The "Emanates" stuff seems to be another way to get more Nephalem powers going, so that's fun. Didn't get a whole lot of time to play yesterday, but got Angelina to 70 and have the first four pieces, plus she had Haedrig make the Captain Crimson's set for her, so she's doing alright.
