In my opinion the Eventide is far better, especially with pitch-shifting & multi-effects. Not sure which model will emulate the exact vocal setting better, but dialing thru the parameters on a preset on Eventide will yield great results. Thats just my 2 cents.

Yamaha uses time based effects while the Eventide is a pitch based box... that is the primary difference between the two.

For reverbs I prefer the Lexicon line of stuff with the PCM 60 / 70/ 80 and 90's being the very least of them that are really useable. The cheaper MPX line is not something I would want to use ....

The reverb in the H3000 series Eventide blows. I have never liked it. Now the newer Eventide models is a much different story. Very good reverb. The H3000 does much better at pitchshifting/harmony and other time based effects very well (delay, chorus, flange, ect)

The Yamaha SPX units are no sloutch in the time based effects as well. The SPX has a better reverb and a better reverb that fits in the mix than the Eventide H3000 series units. But the Eventide offers a sound/tone and effects that can't be easily matched by other units in it's price range new or use.

Like Kurt, I mostly prefer the reverb in the higher end units from Lexicon or TC Electronic.

the older H3000 converters sounded horrible at low volume levels