Well, the actual main reason I upgraded from the F806 was to get more storage space. So, I went ahead and upgraded to the F880 series while I was at it.
I traded in my F806 at Amazon to purchase the F887, so I could not compare side by side. The sound quality, however, is as good (if not better) than what I remember. Extremely superb
I really enjoy F806 which is a player that caught me by surprise, I was expecting nothing special, (maybe iPod level), F806 was basically an impulse buy to play with the Andriod, only once it arrived I heard this wonderful sound come from the headphone out on comparable levels (and in some ways higher) than Colorfly C3, far exceeded my expectations. It now has a permanent place in my stable and pairs nicely with my Rhapsodio hybrid. And it's a pretty sexy looking unit too.