I would also be interested to hear your thoughts on your 840 when you receive it!
Can I just give you a little advise? Trust me on this one
When you receive it don't try to connect any kind of decent speaker cable to it by unscrewing the Red and Black plastic Speaker Terminals on the back and trying to poke the cable in to the hole, they are really flimsy, and way too fiddly if you have large fingers like me which is a real pain.
If the previous owner hasn't already done so, take a small screwdriver and prize out the little black plastic Bungs that are on the head of the Black and Red terminals.
Buy some good quality Banana plugs, fit them on your speaker cables and then insert them where you took the bungs out, like I said trust me on this one, you'll see what I mean.