1st retina had a defective screen: faint vertical line just off centre all the way down the screen (not noticeable unless you're on certain background colours). And as i deal with images/editing it wasnt realistic to live with.
Returned it,
2nd (burn-in tested while in store), immediately noticed faint blocks on screen
Returned it to a rather unhelpful sales assistant who said something along the lines of, "we wont keep opening macs for you since they're tested to apple standards". Excuse me if I'm not prepared to pay well over a grand for a defective product.. FYI: Was a tall guy at the *Cardiff, St Davids* store in Wales, ALL other assistants I spoke to were a GREAT help, particularly the very first guy I'd spoken with on the original purchase. But I was p*ssed with having that answer back (wish I'd taken note of his name).. Especially since I was still in the 14 day return window..
I repeated my request for a new one and he obliged a few minutes later. Thankfully this one turned out to be perfect in every way, it really is perfect. VERY happy with the rMBP, and also with the service of the other staff there. Couldve been better though.