I saw the first season just a few months ago after hearing many good things about the show but not knowing exactly what to expect. Stranded from all the hype, I found the first season engrossing and very well acted (unconventional child actors who don't need to look like models and sound genuine? What madness is this?)
Maybe the biggest problems of the mew season are that stays too close to the first season in some aspects (Joyce going overprotective but from the show's point of view she is right albeit it keeps her family stuck in the trauma of 1 year ago, mystery that sounds hollow and doesn't explore the nature of the Upside Down, new characters who are there just to gove something to do to the old ones but feel awfully underdeveloped, and of course keeping Eleven on the bench for most of the season) while letting the original's strengths go (soulful yet instinctive and feral Eleven stuck in that cabin, breaking the foursome which was in my opinion the real heart of the series: Will and Mike together on their own are such a bore, bless their hearts.)
All of this being said, season 2 has positive things going for it (Max is sadly wasted but is very intriguing with the little she is given to do, and Bill in chapter 9 shows what he could have been if properly developed; Bob is great and Dustin and Steve bromance is very entertaining). For what it is I liked it very much but I think the binge watching format spares it a fair bit of criticism people would notice if they were given time to think between episodes. On the other hand, other people seem to have bought way too much the hype for the series and expect or demand much more than what the show really is. Maybe it is because I saw it away from that, but I find it good without being great. And hey, there's nothing wrong with that.