I've used echo products for a while now. They're known for quality products and have been in the game making audio components for other manufacturers too for a long time.
But after checking out the specs between the two, the smaller audiofire 2 has specs that equal the top of the line versions that they sell.
Unless it's a misprint, the specs differ on the audiofire 4 compared to the other units. Either way you'll get good detailed imagery across the audio spectrum and it's built solid.
I had to send a layla 20 bit joint to them one time back in the day, and it was way out of warranty. But they fixed it free of charge including shipping, which was convincing enough to me to stick with their products.
So I've been swinging with two of their layla 24/96 joints for a few years now, no need to change ships from what I see.
Good choice!
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