Success as measured by struggle rather than in accomplishment conveys the romantic notion that it doesn't matter how well you do, so long as you try.
If success could be defined as merely the amount of effort one applied to any given problem then it would be fair to say that both the Russians and the Americans were 'successful' in the race for the moon, but it was the United States that landed there first. Continuing with that line of thinking, if struggle is all that matters, then the current war in Iraq has been very successful for the United States - from start to present. It looks like they are headed for a lot of success in the future too.
It is important to remember that the struggle to accomplish a given goal is a very important part of success, however, I believe, that it's disingenuous to pretend that success can be defined merely by how hard one attempts to complete their goal.
Success is synonomous with accomplishment while struggle only relates to success in that often a successful endevour was possible due to conviction, deadication, and hard work. So, while the importance of struggle should not be ignored, a success can only accurately measured in terms of accomplishment. The bright math student who correctly completes his homework with very little effort is much more successful than the struggling student who slaves over his work and yet despite his effort does a horrible job.
Success must be defined as the accomplishment. The struggle is merely what helps one complete that accomplishment.
