I'm curious about the opinions on 70mm (non-IMAX) vs Digital IMAX.

What do you prefer if you have tried both. Because those are the only mostly accessible options around the world.

Sound is also something to consider, because depending on the Theater they might have wildy different sound setups even different audio standards.

This is purely my opinion. I see 70mm as mostly a movie scam to extort exorbitant amounts of cash from a ticket for something that's vaguely noticeable outside the aspect ratio itself.

Note that I'm not disputing that there is a visual difference, there is, the image is clearer, shaper, with better darks, but the entry fee paired with how out of the way 70mm is, it's just ends up feeling like FOMO.

My opinion doesn't hold much value since I just dislike the cinema experience in general. I like being able to control the environment I'm in when watching something (pausing, eating, loudness...) and whenever I go to cinemas I have to deal with people having their smartphones screens brighten up, people yapping and laughing at things that aren't funny, eating noises, etc...

I go to IMAX to see less smartphones show up during the movie.

The rest is just icing on the cake.

I've recently been to a planetarium which was pretty cool. It has in theory even better specs: 45 million pixels (8K has 33 million), ~500nits, 60Hz. It did seem to use PWM at very low brightness though

https://planetariums-database.org/list_projectors.php?menu=l...

IMHO, the only reasons for using 70 mm IMAX are nostalgia and marketing. Digital movie cameras have far better color reproduction, more dynamic range, zero frame jitter, and plenty of resolution without grain. They are also small and silent which allows far more interesting shots than what is possible with a 70 mm monster. Kubrick and Lean used 70 mm because it was the best technology available at the time. Today, the best technology is digital.