jj604, How many charges on each of those batteries? It would be interesting to see the same comparison at 50 charges, 100 charges, 150 charges, and 200 charges. The results might be entirely different.
I have also read that batteries of different sizes from the same manufacturer can be different so the 4000mah Gens Ace 25C might be nothing like the graph you have there.
If temps stay around 40C the regular nano-tech batteries are better than the gens ace by quite a bit just going by that IR graph and are much cheaper. My batteries come down barely warm on my Trex 500 so it appears the GensAce is not a good brand to use when you are not stressing the batteries going strictly by your graph.
An interesting thrust test of nano tech vs gensace... It is only 1 sample from each though so you of course can not come to any conclusion but it conflicts with the graph above as the video shows more power coming from the GensAce.