Hey, I just bought the 9800BT. The sound quality is fantastic (IMO, I'm no audiophile, but it sounds perfect for everyday driving). My dad was blown away at home it made my 14-year old factory speakers sound like they were brand new. I did over a month's worth of research into HU and I wound up with the 9800. It's a great buy, especially with built-in BT. I got it off Crutchfield for about $440. Hope this helps.
I have been in to car audio for over 5 years now. I have had a couple of Alpine decks, because of upgrading. I am on my third Alpine now, just bought a 01' Lexus ES300 Coach, and Alpine is by far, one of the best. The one I have now is the 2nd one I bought like 2 years ago when it was new. It is on EBay right now and it is at a great price. Alpine CDA 7894. You get what you pay for though. Pioneer makes phenomenal decks too.