Mercedes S Class W220

[D4MJT]

Previous / Current owners ahoy!

I've never looked at these, but I'm having a peek about and they seem a very tempting proposition...

Apart from the usual colossal borkage factor of any 10 year old uberbarge, what in particular should one look out for on a W220? Do they rust? Where? Any common engine complaints? What about electrics?

Thanks in advance :-)