Re: Danvise Vise?
I've had a Danvise for a couple years. Hundreds of flies later, I couldn't be happier. I've ranged from sizes 2 to 18 and it's worked well with all of them. I wouldn't hesitate to get another one, but so far this one shows no sign of wearing out.
The extension arm is exactly what you thought - to give more room for tying longer flies. I've got one on mine and it works as advertised.