Value Vs. Uniqueness of Research
Two criteria often I consider in making a choice between approaches are based on the value proposition/ addition and the uniqueness of the approach.


Ideally, you don't choose.  A "unique" approach that doesn't add value isn't worth much.  Solving a problem using off-the-shelf techniques also isn't worth much.  What you should aim for is a unique approach that adds value to the research landscape in your field.

But if you must choose, work toward your strengths.  Do you carry a hammer and look for nails, or do you carry nails and look for hammers?  If you're better at finding new tools to attack hard problems, then you're more likely to come up with unique approaches.  If you're better at finding hard problems to successfully attack with a small suite of tools, then you're more likely to add value to those tools.  I know lots of successful researchers in both camps.


  Which one among the two help in quicker publications or
  acceptance rate?


You are optimizing the wrong function.  Your primary goal should be to produce the highest quality, highest impact research, not to maximize the number of lines in your CV.  One good high-impact paper is worth far more than a pile of publications that nobody cares about.