I’ve only put the 12.9” in once, so maybe it gets easier.
However, when I put it in, it was difficult to get the iPad into the last of the four corners of the case. When I say difficult, I don’t mean it requires a huge amount of force that’s beyond me, more that I didn’t like to see the iPad case flex when I put it in. Which it did. I’m mindful of all the reports how easy these iPads are bent.
For reference, I’ve had the 12.9” and 11” since launch and neither are bent. I’ve taken the 11” to work with me 100+ times with me now, carried in the ASK and a leather sleeve. No sign of bending. I am aware they aren’t the strongest chassis we’ve ever seen though, and I simply don’t like the idea of constantly taking the 12.9 in and out of the Slim Folio for this reason.