The iLok license is Standard, or Platinum.  All or nothing.  You cannot use model packs with it, and it will not work with the stand-alone version.  It is plug-in only.  All the plug-ins, like the elements are available.  You can use it on as many computers as you likre, as long as the iLok is attached.

The stand-alone version will allow you to use your model packs.  You can even install it on a computer without a Line 6 device attached, and any model packs you've purchased will also be available.  You can even use non-Line 6 input devices with the stand-alone version.  There are three catches:  1.  Any model packs that are permanently attached to hardware, like the PowerPak, and the FX Junkie on the XTLive, will only be available when the XTLive is attached.  This is not an issue if you purchased them separately; 2.  You can only have four Line 6 devices and computers authorized at any one time; 3.  You only have 10 lifetime authorizations total (so chose carefully)