I very recently started playing PoE as a summoner witch (given that I loved playing a summonancer in D2). Definitely reminds me of D2, though I'm not a fan of the currency system, and although I find the way the skill tree is setup, I'm also finding it even less forgiving then the D2 one, while the min/maxing elements make is seem less intuitive to me.
I also both love and hate that there are no class specific abilities or skills. On the one hand, it's a really interesting mechanic, especially when you can do something like choose between a witch summoner who has minions at max power, or a templar summoner who has less minion ability, but can also fight alongside them. On the other hand, I kind of like being able to say "I'm a necro, I can summon minions. He's a paladin, he can't"