I’m not patronising, just saying don’t give up on it. I’m sure they can speak for themselves without your help, but thanks. 
It’s a great plane, very benign on takeoff roll, so if they are having problems as described on takeoff or taxi, they have to be doing something wrong.
Perhaps it’s a version thing. I’m using version 4.4.0, and I’m not sure that version has made it to the Marketplace yet.
At some point the developer added the static friction options, which help a lot because in general MSFS has pretty poor ground handling. An interesting thread of that subject can be found here:
What I didn’t post previously is I believe the 310 has counter rotating props, which is why I said the 414 doesn’t, which may also explain why the 310 is easier.