I'll help those out here.
I upgraded from a Witson W2-D723V to the AS-7608.
Upgraded features.
1) External mic (plugs in the back) works great
2) Gold case. They claim it won't get as hot
3) DIMM setting has 3 adjustments
4) With remote you can adjust the brightness even more - See #3
5) Has front plug for USB. Back cable plug for USB.
6) 533mhz compared to 400mhz
7) Higher gig sd cards allowed
Downgraded features
1) Red button lights aren't as bright as Witson to match dash lights.
Other features
1) Still can't upload phone contacts
2) Even after purchase Witson was fast to answer my emails (24 hours). Right now Audiosources hasn't gotten back to me in about 4 days
Pricing was $395 plus shipping.
I have the manual in Word, Please email me and I'll send it to you.
BTW....I"m selling my 3 month old in great shape Witson for $325 plus shipping. Even with the other features in AS-7608 I would have kept it if it had an external mic. If interested please contact me.
http://www.witson.com/view_pro.php?id=1424