I have to admit since having the BJCE I have gone off the BJCM a bit, it's still a lovely pushchair but when you have the Elite the BJCM just pales in comparison. I do prefer the Luna over the BJCM as a 2nd pushchair, the fold isn't as good on the Luna obviously & the hood is rubbish in comparison but as it's not a main pram I think it's perfect. It's a bit heavier then the BJCM but pushing wise you don't notice it, well I don't anyway.
The thing is there is fors & againt for both...
BJCM - light-weight, compact, excellent hood, good spacious seat, good sized basket, handy storage bag on the back, good suspension on the wheels, turns easily, easy to fold, easy to open.
Luna Mix - compact fold, nice fabrics & colours, nice big seat, adjustable handle, fairly good size basket, nice to push, fold is straight forward when you get the hang of it, adjustable leg rest, bumper bar, zip on apron.
You have to find what suits you what is perfect for one person doesn't work at all for another. I have to say I am yet to find someone who has owned a Mix & not liked it but the same can be said of the BJCM!