The Weavers have been out of production for I don't know how long; the last V3 I bought was just over a hundred bucks used. I assumed based on the Vortex web site that a new Cossfire II was more than that.
More to the point, the OP suggested he was looking for something "smaller and lighter", that would be used at ranges under 200 yards. The Weaver is on the smaller and lighter end of scopes I've used (and consider reliable enough to recommend), with magnification that's likely appropriate for the use specified. The Vortex is 30% larger than the Weaver, and weighs almost twice as much (it's in the same size & weight range as a lot of 3-9x variables). It also covers a different magnification range than the Weaver: comparing a small, lightweight 1-3x variable to a medium-sized 2-7x, is about like comparing the 2-7x to a 4-16x varmint scope - apples and oranges.
As always, IMHO, FWIW, YMMV, etc., etc.