EXS 24 Logic Sampler Users Group

I'd appreciate opinions from any 1 out there who can tell me there opinion as to what 
virtual sampler works best with Logic 6.3.3, MacG5, OS 10.3.4, 1GB Ram.

Is it GigiStudio? Mach 5? Reasons? EXS?

I'm about to purchase the Vienna Symphonic Library (the Full top of the line pacakge) and 
I'd like to know which of the above virtual samples will let me record & playback a full 
symphony orchestra.  I'm sure I'm gonna need to buy like a ton of more ram for starters 
but other than that which is the best virtual sampler that is reliable, will allow me to play 
back a full symphony score, rarely crashes and intergrates best with my setup.

Thanks for every1 advise in advance!!!  

Maestro
Composer-Songwriter-Producer
ASCAP