Since Apples purchase of Emagic, as we know - or perhaps you don't, the PC version is no longer being updated, but stuck at 5.5 - although this version is perfectly acceptable, it doesn't have all the nifty features that 6 and beyond do - though these are only available on the Apple platform. So there's no big shock news that version 6.3.1 now supports Windows I'm afraid. But there are these new features that I'm sure will come in handy.
Digidesign HD Accel Compatibility – Logic Platinum Mac OS X only
If you are using a Pro Tools HD system with the new HD Accel card from Digidesign, please upgrade to Logic Platinum version 6.3.1 or higher. This is required to take full advantage of the increased number of audio tracks with a HD Accel card.
Smart Snap Option
The zoom-dependent drag grid (Smart Snap – introduced in version 6) is now available as an option. Use the option “Smart Snap when dragging” on the Global Preferences page (Logic menu > Preferences > Global Preferences). If this option is switched off, Logic acts like before version 6: You can move objects quantized to bars, with CTRL pressed down quantized to the Format value, with CTRL and SHIFT you can move objects in Ticks.
In older 6.x versions, hanging MIDI notes were possible in certain situations. Logic Platinum users of TDM systems under Mac OS X you could get the DAE error message –9060 when record enabling tracks in “Punch on the fly” mode. These problems are fixed.
For a full version history you might find this a gripping read.