AstroGrep is very fast, it works great and runs searches smoothly even on HDD, with the difference in speed between the former and SDD not very noticeable.
AstroGrep can show more than just the line search, for example the --context=NUM of a command-line GREP.
PowerGREP has a very easy to use GUI, with a great preview mode that allows you to be sure on what you are replacing.
Configuring how the application works may take some time. Though this is only initially since the configuration is kept throughout later sessions.
BareGrep cannot filter out the irrelevant lines from the log (they are simply colored in a different color).
If you wish to export the results from grep into a text file or any other format, there's no way to do it with GrepWin.
Windows Grep hasn't had a new stable release in a while. The released version has Windows 7 listed as the latest version of Windows supported.
Windows Grep has support for search-and-replace text. This is very helpful if you want to edit files en-masse.