in my opinion the buttons are too close to each other.
the big wheel should be moved further down to have good access to the buttons directly located close to the wheel.
especially play, <-, << and + are too close to the wheel.
I would prefer to have the <- and play moved 'outwards' to be between the other buttons. see my 'screwed-up' front of the radio in the attachment. Allocation of the buttons could for sure be improved by a designer ;-)