Glycinated magnesium is different from other forms because glycine itself has calming properties, it's not just the magnesium doing the work. But if we're talking about actual results, it really depends on the person and especially on what's causing the anxiety in the first place. It's not a magic bullet, and if the attacks are frequent and intense, you really need to figure out what's at the root of it with a specialist. A supplement is just a minor help, not a solution.
What nobody ever mentions is tracking when these attacks actually happen, not just "sometime in the evening" vaguely. Like: is it half an hour after coffee? After specific stressful situations? When you're tired? When you're sleep-deprived? Once you see the pattern, magnesium (or whatever) often works better because you're already dealing with the real cause. If you find out it's linked to poor sleep, magnesium can actually help. If it's tied to caffeine or stress, it might not make much difference without fixing those problems.
Try the glycinate if you want, but do it thoughtfully: make sure there aren't other much simpler things you can sort out first. And if after a month you don't notice any difference, or if the attacks get worse, don't waste time trying other supplements - that's when you need to talk to a doctor or therapist.