The A6 still isn't as fast as the i3, even in photo editing, but it should be ok. It depends on what you are personally comparing it to, ie - what you are used to using. Its about as quick as an athlon x3 430 or a core 2 due E8600. The i3 is about as quick as a core2quad 9650.
Both have integrated video chips, the A6 GPU being better of the two.
The I3 would dominate in transcoding videos because the i3 has a hardware encoder built in. It doesnt sound like you encode videos so this wouldn't be important to you.
If you decide on the A6, be sure to get qualified 1866 ram. Its been posted many times that theres a noticable performance gain over 1600.