The NL's just have that edge to edge quality that the TA's can't match. Honestly you don't see it when you first look through the TA's, but if you do a side by side comparison you can see it pretty blatantly. I think it's important to remember that these were not made to compete with each other, they serve two whole different purposes. The NL is just for pure glassing, whereas the TA's try to give you some glassing qualities and serve as a rangefinder. This is not an apple's to apple's comparison at all.
So what can we compare? We can compare the quality of the image between the two and then decide if it's worth giving a little to get something else. When looking at the center of the image, you couldn't convince me that you can see a true difference. I'm certain there is a mathematical difference in resolution, transmission, and clarity, but not one that my eye can tell. I don't think you are losing much, if anything, by going with the TA's vs. the NL's when just comparing the centered image. As previously stated the NL's edge-to-edge clarity is immaculate, and the TA's just don't have the ability to match it. There is a slight rolling effect on the sides of the TA, which does eat up some of the usable field of view. So maybe you'll have to move your binos a bit more on a tripod to cover a hillside or area that you are looking at with the TA's?? I think you still can cover it all sufficiently without missing much of anything between the two binos.
For me, if I was choosing just one (thank god I don't actually have to make this choice), I would go with the TA's because as a guide I need that instant ability to get a range on an animal. Between setting a client up for a shot and checking on the animal's range and whereabouts, I can't afford to switch up between a rangefinder and a bino a few times. I know that I will lose the animals position if I do that, so I need that all in one unit to be successful. If being able to get instant ranges when you need them isn't of concern for you, then without a doubt go with the NL's.
To sum it up and answer the OP's original question….glass quality, hands down, the NL Pure is the way to go. Functionality, hands down, the TA is your unit, and I don't think that you lose enough glass quality with the TA's, that you will find yourself handicapped out in the field. Good luck!
On a side note, I can't wait to get my hands on the 32mm TA's from Swaro…I am interested to see how much usability I feel like I lose by having the smaller objective, vs. how much I gain by having the lighter and smaller bino. Stay tuned!
Jeremy