I think it will be comparable to Superman in NA for it's opening weekend, but I'll be much more comfortable making that statement when we get actual reviews, which could help or hurt that scenario.
It's amazing to me it has a chance of even being close based on the performance of the past 2 MCU films and the fact that Superman had a crazy marketing campaign the last 4-5 months. Even though I'm hyped about this film being I love the Fantastic Four, a part of me still doesn't believe the hype based on the circles I've been in touch with the last 6 months . In comparison to Superman, which people were always talking about, this film didn't really sustain any lasting buzz after the trailers were shown.