Sonically excellent network player, a few teething troubles

Did the Network Player Denon DNP bought end 2012 720 AE.
I listen to classical music always burn any new downloads to CD explodes at some point the storage capacity of each household. Therefore, I switched from now and save my down loaded CD's etc. from now on hard drive and listen to it on the network player. Sonically the DENON has much to offer, it must be very good building blocks in the D / A converter technology have been installed. However, the device has a few small teething problems. The USB port can connect drives and hard drives. So it is in any case in the operating instructions. Now the catch: The device can not detect any USB stick, even with hard drives, there are problems. Had two hard drives had, both of which were not recognized by DENON. I then phoned Denon and was assured the disks by the manufacturer BUFFALO are ideal. I can only agree, that so whoever buys this unit, then should also necessarily a BUFFALO HDD (for me it is the HD PCU2) down. With USB sticks I've had good experiences with the brand Intenso. For Internet Radio I can not say as much as I do not use this feature a lot. Sonically, there are at the various stations but huge differences.
All in all a very good for the money network player with excellent sound quality.