Very good vise jaws for trout size flies and the 2 knob adustment is a proven effective way to get good and tight on a hook. The array of delrin washers and rubber o-rings on the Odyssey can be a PITA to work with to set up for the feel you want if you really want to give the full rotary aspect a workout. The other thing that makes the Odyssey less solid feeling is the construction of the angle on the arm, which is via thumbscrew and sliding shim/bracket.
If regular use of true rotary is what you seek, spend up for the Renzetti Traveler and justify the 100 percent price increase by amortization over the years. I have to say, however, that the latest version of the Traveler has a cheap look to it vs previous editions.
I tie regularly on the Odyssey, but don't need full rotary, so that full rotation feel and consistency is not that important to me. I just like to turn it a bit to see the bottom of the fly or the other side, or to help wrap something that wold otherwise be awkward on a fixed head vise. Just that little bit of ability to turn is important to me, something I am reminded of every time I tie at a family member or friend's vise that is fixed position. If fixed position seems ok to you, the Odyssey's vise head appears to be the same as the one on the $40 Griffin 1a.
Speculative history. The Renzetti Traveler was a 2 knob adjustment vise when it came out, and the Odyssey was almost certainly Griffin's answer at half the price We are talking 15 plus years ago.