Now I'm torn...both the Peak and Renzetti seem like great vises
The best advice you've received is to make a trip to a shop where you can put your hands on the vises. Try to tie a fly on the "finalists" if possible, then pick the one you are most comfortable with.
With that said, a few years ago I was in the same position. I wanted a new vise, but didn’t want to spend too much money. The Renzetti Traveler and the Peak rotary were a couple of my finalists, and both are good vises.
Here’s my take on them, they differ in two distinct areas. You'll need to decide which is most important to you.
The “fit and finish” of all the Renzetti vises is one of the best in the industry. They make a nice high quality tool. I don’t think Peak does as good of a finish job as Renzetti, but it is a workhorse of a vise that will last a lifetime. I know several people that tie a lot of flies on their Peak vises and they’ve been very happy with them. So, how important is the "fit and finish" of your tools to you?
If you’re looking for a clamp style vise then this may not matter, but the weight deference between the two pedestal bases is significant. The Renzetti is made as a travel vise and it has a lighter weight base. The Peak has a heavy and wide base. The Peak is very stable, but it is heavy to travel with. So, what is more important to you, stability or portability?
Good luck!