Q: Which tastes better, apples or oranges?
A: Eat grapes!
Both tanks are great. I've used quite a few NitroDuck tanks, and they have always performed well. Several people here have AGD tanks and like them. Since performance is not significantly different between the two, I would look at how they will mount to your marker and see if that would be comfortable for you. Also, at that point... looks may be a factor.
Play Honoribly. Only your honor can never be taken from you. You must conciously betray it.