results

Rehearsal ----------------------------------------
uniq   0.270000   0.000000   0.270000 (  0.278307)
set    0.310000   0.010000   0.320000 (  0.314648)
------------------------------- total: 0.590000sec

           user     system      total        real
uniq   0.220000   0.000000   0.220000 (  0.230810)
set    0.300000   0.000000   0.300000 (  0.310188)

Set merge vs Uniq.rb

require 'benchmark'

def make_array
  (1..10000).map { Random.rand(10) }
end

Benchmark.bmbm do |x|
  x.report("uniq") do
    array = []
    100.times do
      array.concat(make_array)
    end
    array.uniq
  end

  x.report("set") do
    require 'set'
    set = Set.new

    100.times do
      set.merge(make_array)
    end

    set.to_a
  end
end