I think the most important things to know of PoE are that although it is very well done it is very difficult and unforgiving with a steep learning curve and strategy that will follow you all the way through the game. I feel it is designed for the die-hard ARPGer familiar with this type of online only game. Although you can play solo you must be logged in at all times. I played fairly well up into level 38, into Act 3 (the last act), but the strategy and planning necessary got the best of me. I'm more adventure and action oriented and I like intuitive games. PoE is not intuitive!
If you are bad at strategy and ARPG that are not intuitive to play then 4--Poor is a fair rating. If you love this style of game then 8--Great and above is a fair rating.
The game is all done in real time--even while pausing solo so you must plan where you park your PC before you take off for the bathroom or a sandwich. And worse, if you portal back to town and do not return within around 8 minutes or so iirc the whole dungeon area you might be struggling through gets respawned which will include a new map and respawned monsters and foes. So for your little venture back to town you get to start the area you were in over again--lots of fun. But if you are into 'farming' this isn't an issue and when you get the hang of it you will manage.
Plan to develop and play around with a number of different characters before you decide on one to play all the way through the game. Better yet plan to play more then one time through the entire game with different characters. Plenty of gamers do this--but not me.
I should mention too that I experienced no bugs or hiccups as far as I went--a really clean graphic experience.
Good luck and skill--you'll need it.