Both the Audio-Technica models are a bit more strident in the treble area than the Alpha. AT loves to push the upper mids, which makes their headphones great for classical/jazz music in particular.
The Alpha isolates better than either of the AT headphones, and of course it has the microphone for gaming. It’d say it’s more comfy than the SR6BT, and about on-par comfort wise with the 1100is.
Beyond that stuff…it’s kind of down to the features you want. The 1100is is the only semi-open headphone, and the SR6BT is the only one on the list with Bluetooth support. They’re all wildly different products with different target users.
Off the cuff, I’d probably pick the Alpha, because it has the most features that I would personally use on a day-to-day basis, it’s quite comfy, and it’s the cheapest at least where I live.