I went from a decent seperates system to a Denon DHT500SD "all in one". My wife could never get her head around how the seperates worked, and used to comment on the number of ugly black boxes that were beneath the television!
The Denon looked much neater sat underneath all on its own, both the missus and the kids got used to using it fairly quickly so everything should have been alright in my world. Nope! I've now gone back to seperates (abeit on a budget this time, and the component parts are silver instead!)..
The Denon was fine up to an extent. Picture quality was good, connectivity was excellent, sound quality was ok. But this is where it let itself down.
The sound quality was nowhere near as good as my seperates system.
To be fair, it had no right to be, and if I hadn't been spoilt with my previous system I would most probably not even have noticed..........but I did.
I also had a couple of little "niggles" with it, which other users have commented on, not enough to make me want to throw it out of the window, but enough to make me wary of future problems.
This is the biggest drawback with "all in ones". As others have mentioned, if you get a problem say with the amp component, you have also lost your DVD player and tuner whilst the unit is away being repaired.
As I say, I have now gone back to seperates, invested in a decent, (to my ears at least), set of surround sound speakers and am really, really pleased with the improvements all round.
I haven't spent a fortune, in fact the price of my new kit is only slightly more than a good "all in one" but I am a lot happier with it.
And if my DVD player or receiver plays up, I can at least work around it, or upgrade the item and build up the system as and when I want.
My missus still commented on how difficult it was to understand how to work it all. My solution? A "Harmony" all in one remote.
Now shut up woman, and listen to the music!
Hope that helps
Rob