SizzlingKeys (Free; Pro version $5) and Synergy (5 Euros, roughly $7) are keyboard controllers for iTunes. Synergy has been made available through Macheist’s Giving Tree for free for the time being.
Both allow you to advance and go back tracks, play/pause, set rating, adjust volume, and more through keyboard shortcuts that function even when iTunes isn’t the active application. (Disclaimer: The free version of SizzlingKeys was reviewed, and Synergy was obtained for free through the Giving Tree.)
Interface
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Both of these apps actually offer similar interfaces. Both are controlled through a preference pane, and display a floating informational panel when you change tracks or play/pause.
Here we see Synergy’s informational and preference panes. (Synergy uses centered panels to show playback information that are similar to the ones OS X uses for adjusting volume.)
Functionality
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Both of these apps are great at what they do. They consistently control iTunes via keyboard shortcuts without hogging resources. SizzlingKeys also offers some extra keyboard shortcuts including: Put computer to sleep, Lock computer, Activate screensaver, and Put display to sleep (the last one is OS X 10.4 only).
The Pro version of SizzlingKeys allows you to toggle the shuffle and repeat modes, skip forward and backward by definable amounts of time within a track, and adjust the system volume (instead of just iTunes’ volume). Toggling of playback modes is also found in Synergy.
Value
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You can’t beat a wellmade free app, and that’s exactly what SizzlingKeys offers. The only case where plunking down money on Synergy is justified is if you really want Growl notifications, which are kind of redundant given the floater both of these apps provide. Even if you want to have control over playback modes, SizzlingKeys Pro is the better deal. Note that Synergy is still available for free from the Giving Tree, so if you want to try it out you can without spending any money.
Overall
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Ultimately, this comparison comes down to two very similar apps, one of which happens to be free. MARS’s recommendation is to download both (while Synergy is free) and see which one you like better. Otherwise, SizzlingKeys offers the most bang for the buck.
