I would really like to back up what noldar12 said. He is absolutely right about the differences between the two libraries. I've been jumping all over the place with libraries and was never satisfied, finally I settled with VSL. The reason is simple, as my budget is quite limited at the moment, I can't afford a full orchestra, but with VSL I can progressively increase my collection. I started by replacing the sounds I found most unsatisfying in the libraries I have, which was the Brass section, and I invested in building myself a good brass section with VSL. Eventually I will replace the Strings, with the reassurance that the Brass integration won't be lost.
VSL also has very strong softwares behind it, from VI and VI PRO to VE, which is fantastic (and free!) which actually compensates the limitations of the software I use (Sibelius). Not to mention Vienna Suite and MIR. If you can't afford VSL SE I would actually go for something really simple (maybe even GPO?), and gradually replace the instruments with VSL as you are able to afford it. EW will make a big hole in your pocket and as far as I know you won't be able to upgrade it without upgrading the whole orchestra.
About the standard/ extended complexity, I would like to help with this because I was really confused and made a big mess of this myself.
VSL Special Edition Standard: Basic Articulations for classic orchestral instruments
VSL Special Edition Extended: Basic Articulations for exotic orchestral instruments (needs Standard installed)
VSL Special Edition Full: Combination of Standard with Extended
VSL Special Edition PLUS Standard: Extra Articulations for the classic instruments (needs SE Standard installed)
VSL Special Edition PLUS Extended: Extra Articulations for the exotic instruments (needs SE Extended and SE PLUS Standard installed)
VSL Special Edition PLUS Full: Combination of PLUS Standard with Extended (needs SE full installed)