strive for the best vs strive harder

Some examples from the web:

• strive for the best
• The doorman and staff always strive for the best and we appreciate your compliments.
• We strive for the best, but sometimes we fall short.
• Our consistent strive for the best in terms of quality, innovation, service and sustainable answers are the main drivers for all our business activities.
• We should strive for the best possible Utopian ideal and work towards that.
• Europe must strive for the best integration of the new Member States.
• While we shall be proud of this strong and healthy DNA, the primary goal of a competitive operation machine today is to continuously strive for the best customer performance.
• It is this belief that drives us to strive for the best possible solution to each design problem.

Some examples from the web:

• I strive harder to live up to that ideal.
• It must strive harder to fulfil its obligations in that regard.
• I endorse the report, but I call on Romania to strive harder towards joining the EU in 2007, otherwise its accession will certainly be delayed.
• The Church needs to strive harder to understand what is happening and adopt a strategy to address it.
• These children also strive harder to achieve their goals, are less violent and are less likely to fall into unnecessary depression during their teen years.
• Envy is a peculiarly human emotion, and can sometimes be immensely creative because it helps us to be conscious of what we value and spurs us to strive harder for what we want.
• Why do I strive to be a harder worker?
• Your service will be all the more rewarding the harder you strive, with a genuinely priestly spirit, to encourage the growth of the local Churches, linking them with the Chair of Peter, and for the good of the peoples.