Pass Labs 350 vs. 350.5 sonic differences?

Is the .5 series that much better? I could save $2000 buying the x350 at this time so I am thinking of pulling the trigger. Thx.
Nickt, the short answer is the the .5 series is signficantly better sonicly the 1 generation X series amps. Read my review here on the GON regarding the X-350.5 for details why it offers much better sonics then a 350. So, save your money and go for the .5 amp, don't get the 350 even if it saves you so money.
Thank you Teajay. I will pass on the original X series after reading your review and comments.