EXS 24 Logic Sampler Users Group

I recently bought EXS thinking I'd try out a software-based sampler 
to see if it was good enough that I wouldn't still long for a 
hardware-based solution.  When I tried it out I experienced some
noticeable latency when playing the EXS in real-time, but to be
fair this is the kind of tradeoff I expected in a software-based 
solution and presumably the problem goes away in playback.  On the 
other hand there was something not quite right with the sound.  
Samples like organs sounded great, but some of the samples like piano 
had this weird aftertone that I think is referred to as an aliasing 
problem.  For instance I loaded up a 64 Mb Akai piano sample and it 
didn't sound any better than some < 1Mb samples I've heard.  A number 
of the samples that came with EXS24 also displayed this problem.  My
question is, is this typical or is there something wrong with my
setup and/or have I found some kind of bug?  I'm running EXS on a 
400 Mhz B&W G3 with 448 Mb of memory and using a Motu 2408.  I'm 
running OS9 with virtual memory off.  I pretty sure the problem is 
just with EXS because all my audio tracks in Logic sound great as do 
all the Logic effects plugin's.  Help!!!  Thanks.