The LE edition of Digidesign's Structure RTAS sampler workstation may not feature all the bells and whistles of it's bigger brother, but regardless, it's an amazing instrument for Pro Tools users, and comes at nearly a third of the cost. You lose some features, like sample mapping and a few of the in-depth editing features of the standard Structure, but the ability to integrate a mixed bag of samples and tweak them into your own simple and/or complex sounds is still the big draw.
Structure LE Sampler Virtual Instrument comes with a 3GB sound library from the Digidesign Advanced Instrument Research team (A.I.R.), and gives you the freedom to add samples from other unencrypted sound libraries (KONTAKT, EXS24, SampleCell, etc.)you may already own too (up to 24-bit, 192kHz, 7.1 surround). The 8-channel multitimbral sound engine offers a maximum of 256 polyphony per structure instance and 32 polyphony per part, with 3 stereo auxiliary outputs. The multi-effects processing engine includes simplified controls; more than 20 professional stereo and surround effects algorithms; the ability to add and edit an unlimited number of effects in any patch; and a global effects page featuring 4 internal effects busses, 4 effects inserts per bus, and a master insert bus. You also get 6 Smart Knobs and full MIDI Learn functionality for real-time control, drag-and-drop sample import from the Pro Tools environment, an integrated database and browser, and full save functionality--all features of the normal Structure software package.
If Pro Tools is your DAW of choice, and you're wanting to add samples into your virtual canvas, why not go with a package optimized exclusively for your workstation. Since both products were developed by Digidesign, you'll experience the highest level of reliability.