Again, I would not recommend IEP for a beginner library. Overall it is not as versatile and vast as something like Komplete and is only RTAS, which could bite you later. IMO, IEP can be very useful as an add-on only after one has a healthy cross platform set of VIs.
The Structure video actually displays that the sounds being used are including with IEP. Just keep in mind that Structure is not 64 bit, but allows disk streaming for larger samples. If you are thinking about EWQL Symphonic Orchestra, then get the multi-format 64 bit version from EWQL.
Mach Five is Oooookay and I've seen guys create nice patches with it. The sampler is cool but the library is cheese compared to competitors and it can't even be compared to Komplete.
Just my two cents.
