I went from a regal to renzetti. I can only say that I miss the convenience of spring loaded jaws and the ability to lay my hand on the sloping Regal head, and it's solid feel. But I would never go back simply because even tho I don't rotate the fly to wind stuff (I thought that was why I was getting rotary), I do rotate it all the time to work on different 'sides' of the fly, or to make dubbing easier (start perpendicular to plane of hook) or for whatever reason. In fact winding parachute posts, I'll rotate it horizontal, and then rotate it in clamp so that the post is oriented to my tying hand as the hook eye would have been, making that much easier.
I was tying on a old Regal with std jaws. For me anyway the std jaws engulf the smaller size hooks and I don't have good access to the back of the hook. On larger hooks the vise is great. When I looked into the smaller stainless and midge jaws they were too expensive in my opinion (175.00 - 200.00). This got me looking into buying another vise and I settled on the Peak. Great vise for the money and extra jaws are affordable although I can tie down to size 22 with the std jaws.
I recently acquired a HMH Spartan at a auction for 50.00. The vise was dirty but it cleaned up well. Its decent but I like the Peak much better.
Get a Peak rotary, I bought one and like it. I did try a Regal at a group Beer tie. The Regal nice but doesn't have rotary and cost more. I think you will be happy with the Peak rotary, I am happy with mine.
Ive been tying on a Renzetti for over 30 years. My first was the Traveler, I still have it and use it, although I tie on the Presentation at my desk. Fine vises no matter which you choose and true rotary.
I went from the Renzetti to the Peak a several years ago. I prefer the Peak. It has a rock solid build and the jaw adjustment on the Peak is a much better simpler and faster to use design. I have tied #22 curved midge hooks to large streamer 1/0 on it.