As someone who hasn't spent a ton of time extending any CMS but uses a lot of frameworks, I enjoyed EE too during the short amount of time I used it. Out of wordpress, drupal, and EE, EE is the one where writing plugins felt like normal programming since they hooked right into code igniter. (Not sure how things have changed in the last couple of years though.)

Still pretty much the same.

Main downside of EE that I remember is that when you add new functionality, the way it accomplishes this is by dynamically altering a table schema to add new columns. You can easily get up to hundreds of columns. That just seemed like it had to be a wrong approach to me, but I didn't investigate further.

Is ExpressionEngine better for medium to large sites? I've worked with it a bit and did not like it at all, just wondering what it's better for. Did not seem as intuitive for content creators or mom and pop site users.

I don't think EE is intuitive for Mom and Pop people. If that's your market then WP or something else will probably suit you better.

But if you're an actual business who can spend an hour training your Content Manager(s), then it's worth it, IMHO. It's a dedicated CMS and IMHO better to work on than WP.

It's annoying to configure, and the community is infinitesimal compared, but it has a stellar security record, and it's feels much more extensible.

The main thing to consider is that the community isn't like Wordpress's, which is often a pretty big deal when tussling with it.