I don't know about fly tying models, but I have a pair of left-handed regular Fiskar scissors that I've used for at least 20 years and my wife has a pair she has used since 1980 and still loves them. My mother swore by them as well. They have been around for many years and make a quality product. If I came across a model that was suitable for tying I would have no second thoughts about buying them.
A right emblem it may be, of the uncertain things of this world; that when men have sold them selves for them, they vanish into smoke. ~ William Bradford
I finally realized that Life is a metaphor for Fly Fishing.