theoretically, if we could install (for example) an Intel quad processor on a digital effects unit, and use its speed to it max power to process the signal with the correct algorithms and factors, ANY analog effect can be emulated, right down to the nuances of tubes. dependent sa processing speed kasi ang resolution ng emulation.
but its impractical to put a 3.2Ghz processor on a digital effects unit still because of price.
so when the time comes when technology is cheap enough to put a dedicated Intel 3.2 ghz processor on an effects unit, thats the time you'll be hearing 99.9999999% near-analog tones..... you would never tell the difference. i think in less than ten years we would be seeing digital effect processors like that.
btw im more of an analog guy, if i had to choose between the two id go analog. my username is not digital effects related