ONE XQD slot is more reliable than 2 SD slots.
XQD is far more robust and reliable than SD. You're literally more likely to have BOTH SD cards fail in a Sony vs. the XQD in the Nikon D850 or Z camera.
One of the primary selling points of XQD (beyond speed) is that it's practically bulletproof compared to SD.
Have a great weekend!
Rob
Have you found any objective reliability specs such as MTBF. I looked and didn't find anything.
MTBF is probably not an applicable measure, and would be deceptive anyway.
Remember, the fretting here is not about any and all forms of card failure: it is about the specific type of failure where the card allows the images to be written on it, but then fails in such a manner that those images cannot be read off it. Plus, cannot be recovered with recovery software.
It does not include many, many other failure modes that stop the camera recognising the card, because then it says 'No card" and you put another one in, and no photos lost.
So what we need to find is the frequency of occurrence of the one, specific failure type that irrecoverably loses images after they have been taken. You are not going to find that, not only because it is such a small category of sub-failure, but because most of the situations that could lead to it involve thoughtless or abusive card management by the user. You don't want to count those modes either.
Of course, if you are actually a thoughtless and abusive card manager while working professionally for paying clients, then, firstly, you are disrespecting your clients and probably should find other employment for their sake, and secondly, good luck with a two-slot camera because there are plenty of ways you can wreck both cards at the same time.
If your preferred model of camera for paid work happens to have only one slot, then if you:
- buy top quality cards from a reputable supplier;
- replace them every two years or so, or whenever an event occurs that concerns you;
- when you buy a new card, before first time used, test each card with a full read-write cycle and check for errors (eliminating the risk of the card being faulty upon purchase, the most likely cause of failure other than abuse);
- never modify the card's contents off-camera and re-insert and keep shooting -- always reformat if you modify the contents off-camera;
- other general good practice and care;
- (optional, if you can't help fretting) change card several times during a paid session and/or use a wireless transmitter to send photos in real time to off-camera storage;
....then you can proceed with confidence that irrecoverable loss of images due to good-practice card failure is one of the least likely ways that you could lose images (at least several of your lifetimes of weekly paid gigs per failure), and you should be fretting about all the other things that could go wrong and ruin the session's images.
cheers