You'll get lots of different answers depending who you speak to, but you're right, he's had a poor 18 months.
He's very one footed, with an excellent cross and ridiculous close control - so I think he's mostly best either on the left if you want to use him as a traditional winger, beating his man and pinging a range of crosses in. Or on the right, if you want to have him cutting in and acting as a more direct threat. He's got a great range of passing on him too.
Don't think he'd do much use in the middle of the park as his one-footedness is more of a weakness there.
We all wanted him to stay generally, I thought he'd really kick on in a lower league and under Kompany's more progressive tactics (he was partly at fault for his poor output, but Dyches tactics didn't help), but this fee is far too good to turn down. He could be worth it, but you'll need to get his all-time-low confidence back up, if you manage to unlock his potential then he could be fantastic.