The best replacement for parallels is vmware.

The best alternatives to parallels are rated as following:
★★★★★  vmware
★★★★  fusion
★★★  crossover
★★★  bootcamp
★★  vmware fusion
★★  virtualbox
★★  boot camp
★  vm fusion
★  dual boot
★  virtual pc
★  virtualbox mac
  bootcamp gaming
  vm
  meridians
  fusion for mac
  cpanel
  vmfusion
  fusion mac
  virtual box
  vm ware
  vmware for mac
  bootcamp windows 7
  vmware fusion 3.1
  boot camp for mac
  vmware fusion 3
  vmware fusion 4
  wmware
  vmware for gaming
  latitude
  wineskin
  vmware workstation
  latitudes
  vm fusionware
  bootcamp for mac
  fusion 3
  vmware mac
  vmware performance

Your alternative for parallels is not listed? Suggest!
Speaking about parallels, one probably shouldn't forget about bootcamp.

Other search terms related to parallels and their ratings are:
★★★★★ bootcamp
★★★★★ windows 7
★★★ boot camp
★★ mavericks
★★ vagrant
★★ retina display
★★ ubuntu
★ mountain lion
★ os x mavericks
★ boot camp partition
★ snow leopard
★ windows 8
mac
You have in mind a companion for parallels and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of parallels in all years. Click on graph for more.
parallels
vmware
fusion