Sounds like you know your tempered glass.
Could you please share your opinion via rank on the different brands. Such as, I know zagg makes T-glass too, though I wouldn't know where they stand in comparison to the protector from At&t or the Nilkin you just posted.
Just to get an idea.
I haven't used all the brands and it's really hard to tell base on 'specs' that they list. Generally you get what you pay for and the only way is to get feedback by other users. Some companies have better warranty service than other. Generally if you pay less than $10 you'll get something average that'll be okay for the job. Even a $3 one will protect your phone, it just will be a finger print magnet and not smooth.
The important thing is to get one that have good oleophobic coating so it feel smooth just like the real glass. Some are better at resisting scratches. Some are more brittle than other. The thinner ones (less than 0.3mm) are rated at 8H and more flexible, but is more fragile. I tend to get ones rated at 9H, but in the end of the day, these rating are just claims that doesn't really mean anything.
Nilkin seems okay to me, not the smoothest oleophobic but still very acceptable. I like Monoy and TechPro a lot. Monoy are very smooth and TechPro ones are quite thick compared to the rest. I have bad experience with iBlason which seems a bit fragile.
Right now I'm interested in a brand called DimoGlass which have sapphire coated tempered glass. They are very expensive, but they have no question asked lifetime warranty. They don't have anything for Motorola at the moment though.
From my experience, if you have a baby or drop your phone often then you will need a tempered glass screen protector. It won't resist the baby throwing it face down onto ceramic floor more than a few times, but it will protect the phone. Once it's crack, especially across the entire piece, the level of protection for the real glass below can be significantly reduced.