As to the OP's question, I think the weaver style is a bit better than the dual dove tail. either will work well but it depends on the specific application.
Weaver style bases absolutely SUCK if they are not anodized aluminum or steel (most picatinny rails are anodized but make sure) and as mentioned the dual dove tail is a one use deal

p.s. either of these two method's is superior to the windage screw rear base that is perhaps the worst idea EVER !!!!!!

Last edited by rockchuck828; 11/07/10.