I have xacto, excel and zona...plus other off brands. Side by side I see no difference in the blade handles, saw blades, plastic saw blade handles or mitre boxs. Depending on age, they have different styles and cosmetics but the designs cross over to each other. I bought a zona aluminum mitre box last weekend and compared xacto, excel and zona boxes side by side...they are identical and appear to be made in the same factory with different branding. There was a few $ spread between the xacto and zona box. My heart said buy the xacto but my brain said buy the zona.
Since most of my stuff is so old and in pieces I've been thinking about buying a nice new kit. Street price for a nice exacto set is $75...and street price for an identical clone (probably china) is $15. No wonder xacto's presence is shrinking.