It's extremely good, i will say this game seems more orientated to a casual fan base player rather than say d2 or path of exile hardcore type of player.
I have played the sorc now to level 24 and the combat feels absolutely fantastic, the skills for the sorc are exceptional and using them just feels incredible
There is so much to do, almost too much, quests everywhere, lore to listen to, side content, and events all over the place, map is gigantic.
The only issue i have, is loot is too easy to get, i am already basically decked out in legendaries, and although legendaries are not the best items you get, those would be unique's which is another tier higher.
I do however think some of the itemization blows, they are using a power score rating system, the more powerful items you equip the more damage you basically do.
There is some nuance to that of course as you can have very good rare items with stats you like being better than legendaries, You can also disenchant a legendary item and transfer that particular unique spell skill/ability to that rare and in the process turn that rare item into a legendary item. (it's not as complicated as i am making it sound)
At present, i would give this game a solid 9/10 and for more casual gamers this is 100% a 10/10.
If you have friends and family that dont care to much about theory crafting or looking at spread sheets, and just wanna have mindless fun, this is it.
Possible game of the year for sure.
@Gediminas, that big man slut has a barb at level 25, has played none stop for two days and is in a coma as we speak, if melee is more your thing he would be a good person to ask on how that feels.