The have a lot of choices and their site is a bit confusing to me.  I do know you can start off with a "special edition" for around $500 or less and add to it.

The Vienna Special Edition Volume 1 sounds pretty darn good to me.  It's $355 at Sweetwater.  I need a full orchestra to replace SO Gold, and this may be the comparable library from VSL.  

Just remember that it requires an eLicenser to work. That may be a problem, given the whole bootcamp thing since those DRM dongles are rather fussy.

I've been emailing back and forth (over the weekend) with Paul from VSL.  He is a great guy and answers questions on their forum, and does the videos.  Customer service over the weekend?! The "culture" at Vienna is markedly positive.  He was even interested trying to figure out why Play won't work in Bootcamp (more interested than EW support was!).  And the Vienna Instruments Player is lightyears ahead of Play in terms of flexibility and simplicity.  I should have gone with VSL from the start.
 
Unfortunately both VSL and EW require a dongle.  Hopefully VSL's eLicenser will work in bootcamp.  I have to prove that out.  However, I do know someone that is using it already in bootcamp with no problems.

If you get it let us know how you like it.

Update - I bought Vienna Symphonic Orchestra Special Edition 1 last week and started using it yesterday.  I've converted one project from EWSOgold to VSL.  The sound quality is just as good (or better) than SOgold. 
 
The Vienna Instruments software is really well thought out.  You can go from very simple to very complex with their easy to learn Matrix.  You can build your own set of articulations extremely fast.  It is easy to learn after watching a couple of Paul's videos.  They have presets of collections of instruments that you can use which are totally consistent with one another.  Or you can build your own.  
 
This program is totally integrated with Vienna Ensemble which is also really cool.  It has a mixer where you can control panning and use any of your installed VST effects.  Each of these programs - Vienna Instruments and Vienna Ensemble are available in "pro" versions which have even more bells and whistles.
 
So far I'm very happy with VSL.

Very interesting and appreciated. 

Vintagevibe - I'm in the middle of converting my second project which has some subtleties to it.  VSL continues to sound great but comparing back and forth between VSL and SOgold I'm finding that the reverb is a bit lacking.  It is not a bad sounding reverb, it just is a bit one dimensional - which is part of their strategy.  It is not standing up to the spaciousness of SOGold where the "baked in" room sound of SOGold does come in handy, or their many convolution reverbs that are included.  I'm sure I could overcome this with a great reverb intended for this use.  VSL has their MIR reverb which looks fantastic, but it a pretty large investment.  They hook you on the ease of use and the great sounding raw sounds, and you end up wanting to spend more.  I'm going to have to solve this issue, because I am taking a step backwards with the VSL simple reverb.
 
Vienna Instrument continues to be easy and powerful to use.  I'm using their Velocity Layer Crossfades which are super easy to set up and gives me nice natural sounding swells / expression.

Anyone tried the Project Sam OE ? Spitefire Albion series is epic also ;)

Wow I just checked out the MIR price.  That's bout $900!  You can get the Lexicon Native PCM for $600.  I'd think that would be a better investment and they are seriously lush.