I have the 785 for more than half a year now, In terms of quality and options its practicly infinite. Its so vast in it's tunning offerings that at first I was lost...
The quality is to die for especially at it's price, you wont get 6X6V outputs running 24bit anywhere else.
But here are the drawbacks I've found:
-Made for high mount dashboards only, Mine is mounted low and visability is quite poor.
-There is a Pause button but no AT button as my old Sony Xplod had which I've grown acustom to.
-Random setting is totaly screwed up, if you leave it on RND and wait for a song to end it randomises the songs but if you skip then it goes to the next in line (WTF?!)
-When running from my USB disk-on-key it freezes from time to time (once every two weeks) but simply changing sources fixes it, so its just a tad annoying.
Bottom line is, its an awesome HU and I for one can recommend it as long as what i've stated above wont drive you mad.
Hope it helps.