I’ve used both quite a lot over the years and up until recently was always leaning towards the Blackmagic side of things. But to be honest, if I was setting up a suite now I think I’d probably head down the AJA route.
I’ve got an iO on my home suite which I had one problem with – the red on the component connection stopped working. Sent it back from where I got it from, they sent it to AJA. And rather than fixing it, AJA just swapped it for a new one.
Any other problems or questions I’ve had have always been answered within a few hours (I’m in the UK, so sometimes have to wait for them to get out of bed haha!)