Hard to say because there's no info on how you route sound I and O of the Eventide. The FireWire is a digital protocol so it doesn't convert per se. If your sound is converted by internal or external converters, there will be a difference depending on how they sound and what is their quality. The Eventide converters are very good and sound thick and lush and you should expect them to sound better than a 1500/2000$ computer audio interface.
As far as what Logic may do to your sound… well this is an impossible question. There are just too many variable factors to consider….
all the best
I
