The ASUS P8Z77-V LK is the same price ($115) as the P8Z77-V LX, at least on this side of the pond, the main difference being that the LK can do SLI / CFhttp://www.newegg.com/Product/Product.aspx?Item=N82E16813131837
The LK is aboard I have used many times in budget based systems .... only odd issue was CPU LED being on for a GFX card failure. As much as I like the board, with 1155 being a dead socket, I'm buying only 1150 socket boards for new builds today
The budget board I had been using to date was the ASUS Z87-A ($140) but with the MSI Z87 now at the same $140 price, it has a better feature set, 22 Motherboard awards, better performance, better user feedback and MIL Spec components.http://www.newegg.com/Product/Product.aspx?Item=N82E16813131981.http://www.newegg.com/Product/Product.aspx?Item=N82E16813130693
As for your questions "do mother boards matter ?" ..... Id say so.... kinda like cars....they both get you to work each day, but some have better performance (acceleration / braking), better efficiency (mpg), better features (AC, sound, traction control) than others. More and better BIOS features, better overclocking performance, better / more robust components, number of clots, slot spacing, number of fan headers, type of fan headers, type of LAN, sound etc all may have an effect on which you choose.