It all depends on your sensitivity to eye relief. I find the TA11 more natural and causes me less eye strain. I dont feel comfortable at the ragged rear edage of a scopes field of view. I feel like I am crunched way into the scope using a TA31/TA01 series scope.
Also because the scope is further away from my eye and the field of view is smaller the TA11's magnified field of view which covers the unmagnified field of view is literally half the size of the TA31 while in use. This allows me to have a greater situational awareness than with using the TA31/TA01 scopes. I am less likely to get "lost" in the scope and not be aware of my surroundings. Also the larger exit pupil of the TA11 has NOTHING to due with low light viewing because the TA31 is alreadyas large as you need it to be. However it allows you to have your head slightly more left/right/up/down before you begin to lose the sight picture. This is of course just an extra mm in any direction but to me its noticable. To me 1/8 of an inch of difference in optics height is a huge difference. You may not notice small things as much as I do.
The smaller circular area covered by the TA11, its larger tolerance for non perfect head positioning and the fact it has .308 calibrations which match up with 75 and 77 grain ammo where as the TA31 does not make it my personal favorite.
I REALLY wanted the TA31 because it was lighter, cheaper, smaller, looked better and had more magnification. But in the end what worked better in the ergonomics department FOR ME. Turned me to the product that was better in use instead of on paper.
If you dont have the "need" to get into the scopes "Sweet spot" and can sit back at the scopes maximum eye relief the TA31 may be perfect for you. For the reasons I wanted it over the TA11.
Also because the TA11 has greater eye relief you can shoot more easily from improvised positions you might find yourself in such as on your back, etc.