Time for a change

I've owned my Canon 5D Mk II since before my nearly-6 year old was born.  It and I have been through some rough times, good times and great times.  However, it's age is showing and I have needs and desires for higher ISO capabilities.  Canon are tempting me with a £200 cash back offer on the nominally "lesser" 6D (which shares the same sensor as the unaffordable 5D Mk III).  The 6D gets rave reviews.  London Camera Exchange are offering me £500 trade in on the old girl.  The £1,100 list price becomes £400, and granny has dished out a few quid to her children as a result of trading in some shares.  No need to think about it!