Seen this. I'll echo Ork. It really is extremely average. It's not the worst X-Men movie as that would take some doing, but the whole thing is very X-men in name only & feels closer to something like one of those Netflix marvel shows than any of the Avengers movies. These Fox movies are still grounding themselves to what was acceptable in 1998 & they haven't moved with the times at all.
Its worth pointing that Sophie Turner is an absolutely horrendous actress. The casting for the new X-men series has been poor in general and theres a few people in this who are really bad (Hoult & Law always stink out whatever scene they are in), but Turner really takes it to new lower levels. I was thinking at a part when Jessica Chastain was standing next to Turner how much more fun she would have had with a Phoenix character role, but instead Fox just hired a younger woman they saw on tv with (dyed) red hair instead. There's another bit where someone is talking about the Phoenix being all rage & desire (not sure how they know that without having read UXM #135) and it cuts back to Turner & she looks so bored I thought she was about to fall asleep.
Simon Kinsberg should probably stop trying to make movies about the Phoenix now.