I thought the episode was great. I kinda wish we got more of the real Jean, but the bits we got were incredible. The way she showed up like Jesus to cleanse the "Inferno"? Plus her psychic form and her mental "battle" with Madelyne were amazing. I know she fainted a bit, but in this case it was understandable considering she was physically debilitated and traumatized, without being able to fully control her powers. But they let her be competent and leave the fainting for after the job was done, which is the most important thing for me. Her iconic backstory being included was also nice. Her moment with Logan was sweet.
Madelyne's story in general was pretty good, they managed to make her feel sympathetic without villainizing Scott which was a good thing. They managed to evoke her and Jean's battle in the original event and also their reconciliation. It's kinda unfortunate that they did the whole story in just one episode, cause it was definetely a bit rushed, but if we accept that restriction they did the best they could. The Inferno being to show the X-Men their own fears was a clever idea, the horror visuals were on point. Plus Maddie got a damn magical girl transformation, anime laugh, and her design was incredible. The Madelyne Pryor name coming out of nowhere in the end was really awkward though.