bench.rb

require "benchmark"

float_array = 100000.times.map { rand }
1000.times { float_array << nil }
float_array.shuffle!

Benchmark.bmbm do |x|
  x.report("any?") { 100.times { float_array.any?(&:nil?) ? nil : float_array.min } }
  x.report("all?") { 100.times { float_array.all? ? float_array.min : nil } }
  x.report("min block") { 100.times { minimum = float_array.min { |a, b| a && b ? a <=> b : -1 }; minimum == -1 ? nil : minimum } }
end

Results

Rehearsal ---------------------------------------------
any?        0.000000   0.000000   0.000000 (  0.000885)
all?        0.000000   0.000000   0.000000 (  0.000279)
min block   0.960000   0.000000   0.960000 (  0.958517)
------------------------------------ total: 0.960000sec

                user     system      total        real
any?        0.000000   0.000000   0.000000 (  0.000886)
all?        0.000000   0.000000   0.000000 (  0.000297)
min block   0.970000   0.000000   0.970000 (  0.974703)