No offense man; those are about the WORST-looking pictures you could have posted for either character.
Anyway, slight advantage to Namora. She had a longer career than her daughter (active during the 1940s and 1950s, then perfectly preserved a la Captain America, if memory serves).
Namora should have slightly more experience fighting whether solo or with various teams than her daughter as well (i.e. Agents of Atlas, The World War Hulk coalition, etcetera).
I'd be interested to see which one, mom or daughter, has the greatest strength feat to their credit. Certainly neither is a slouch in this area ...
I'm pretty sure Namora is more powerful. She has been stated to be namor's equal from her conception in the golden age to her reintroduction in recent years. She lacks the feats to back this assertion, but she has some nice ones
http://www.killermovies.com/forums/showthread.php?s=&threadid=512641