benchmark.rb

require 'benchmark'

def v1(value)
  value || "-"
end

def v2(object, method)
  object && value = object.send(method) ? value : "-"
end

Benchmark.bmbm do |b|
  k = Struct.new(:val)
  
  o1 = k.new(20)
  o2 = k.new
  o3 = nil
  
  n = 1000000
  
  b.report("v1 o1") { n.times { v1(o1.val) } }
  b.report("v1 o2") { n.times { v1(o2.val) } }
  b.report("v2 o1") { n.times { v2(o1,:val) } }
  b.report("v2 o2") { n.times { v2(o2,:val) } }
  b.report("v2 o3") { n.times { v2(o3,:val) } }
end

Results

Rehearsal -----------------------------------------
v1 o1   0.400000   0.000000   0.400000 (  0.532133)
v1 o2   0.490000   0.000000   0.490000 (  0.904147)
v2 o1   0.570000   0.000000   0.570000 (  0.989526)
v2 o2   0.670000   0.010000   0.680000 (  1.149990)
v2 o3   0.340000   0.000000   0.340000 (  0.540038)
-------------------------------- total: 2.480000sec

            user     system      total        real
v1 o1   0.400000   0.000000   0.400000 (  0.636844)
v1 o2   0.490000   0.000000   0.490000 (  0.810837)
v2 o1   0.580000   0.000000   0.580000 (  0.902966)
v2 o2   0.670000   0.000000   0.670000 (  1.116346)
v2 o3   0.350000   0.010000   0.360000 (  0.546391)