BD-F8900 problems, experiences

[evsp]

Hi all,
I am new in this forum. I own a BD-F8900 about 14 months ago, but frankly speaking I was never fully satisfied with. For watching movies its perfect, except the fact, that sometimes it hangs when I am browsing in external or internal HDD contents. Often it take minutes to open a subfolder. Sometimes it operates well, sometimes very very slow... The other problem I have nowadays, is playing FLAC music from external HDD or pendrive. The music is distorted. MP3 sounds well. Also Movies from external source even full HD BD rip in MKV played well. Does anyone has similar experience? Shall I bring it to service?