First, the minuses: **EDIT** There aren't any!
1. **EDIT** The CEO replied to a thread on PH and stated: "We're fixing the send feedback function in the app so it opens an email form. This is a bug and wasn't intentional." Fixed in version 5.3.1!
You apparently can't send feedback in the app without a premium subscription - we're not talking "I have a question about this content", I mean "There is x problem, thought you might want to know."
2. **EDIT** As per developer response, they've updated their site, and it no longer throws this error!
Tapping "App Support" in the App Store took me to 'downloadpy.com/support-form', which gave me an "AccessDeniedAccess" error page (on 2017-06-19, if it's fixed by the time anyone reads this).
3. **EDIT** This is resolved in version 5.3.1 - excellent!
There's a couple spots where the post-answer info (in the ribbon) cuts off mid-sentence, and there doesn't seem to be any way to see it all; trying to scroll just results in moving the ribbon up and down.
Now, the pluses:
I've completed a number of courses, and I really like being able to see the output as you change variables. I also like the "put these operations in order to get the desired result" and "can you spot the line with the error in it"-type questions.
Most of the content has a nice, gradual, logical flow as you build upon information from lesson to lesson (though I'll say that the SQL lesson takes a sharp uptick in difficulty later on, requiring guesswork). It's been a pleasure so far, other than the above niggles.