- Launches apps with a keyboard shortcut and a tiny bit of typing, but that's just the beginning
- Open documents, contact information, websites,
- Search the web
- Append text to a text file, such as an item on a to-do list
- Easily manipulate text files
- Compose a new email
- Copy, rename and delete files
- Expand functionality with plug-ins
- Create triggers for amazing custom functionality (like iTunes control or making a file upload service)
Quicksilver is an incredible application, and looking at its feature set (plus the plug-in and trigger examples included) should be enough to win you over. Just as a simple application launcher it's incredible, because it's so fast and learns your typing patterns to find things better. Most application launchers expect you to type "iTunes" or at least "iTun" if you want to launch iTunes, but Quicksilver will understand mistakes like "itn" (or worse, once it gets the hang of the errors you make). It's pretty incredible.
Quicksilver's development roadmap has been a little bumpy over the years, sometimes going too long without an update and getting a little buggy in new versions of Mac OS X. Things seem to have changed for the better recently, so this may not be much of an issue going forward. But Quicksilver does have its moments of slowness, which you only really notice because it's generally so fast. Every once in a while it will lag when you try to bring it up with your hotkey of choice. This is obviously not a big deal, but it makes you so used to not waiting that when it does make you wait it feels more annoying that it really is. Also, it only scans its catalogue of searchable data every 10 minutes (or less, if you prefer). This is really only ever an issue if you install a new app and immediately want to launch it with Quicksilver. It'll often pick it up before 10 minutes have elapsed, but not immediately. These are both very tiny problems, and overall there is hardly anything to complain about.
Alfred is Quicksilver's biggest competition. It's an excellent application launcher but it doesn't learn your habits quite as well as Quicksilver and operates in slightly different ways (which you may or may not prefer). It's particularly good at handling search functions, whether it's on your computer, the web, in the dictionary, etc. It lacks some of Quicksilver's customisation features, but you can add them by purchasing a "power pack" for approximately $US20. Some of these advanced features are more elegantly implemented. The power pack also lets you sync all your settings between computers, which is pretty useful if you make several customisations.
Chuck (our review) is a nice option if you just want an incredible minimal app launcher with little-to-no special features. Chuck just lets you type the app you want, press return, and launch it. It also lets you assign typing shortcuts, so simply typing "F" can launch Firefox and so on. If all you need are the basics, Chuck is a good choice.
There are, of course, different styles of app launchers as well. Apptivate lets you assign hotkeys to apps for quick launching. Apps like Bevy and Overflow give you a more OS X Lion Launchpad-style experience. And, of course, there are several others. If you've got a favourite app launcher we haven't discussed, share it in the comments.
Lifehacker's App Directory is a new and growing directory of recommendations for the best applications and tools in a number of given categories.