What do you think about using this style?
For all breakpoints which are mostly for "mobile device" I use min(max)-device-width and for breakpoints which are mostly for "desktop" use min(max)-width.
There are a lot of "mobile devices" that badly calculate width.
Look at http://www.javascriptkit.com/dhtmltutors/cssmediaqueries2.shtml:
/* #### Mobile Phones Portrait #### */
@media screen and (max-device-width: 480px) and (orientation: portrait){
/* some CSS here */
}
/* #### Mobile Phones Landscape #### */
@media screen and (max-device-width: 640px) and (orientation: landscape){
/* some CSS here */
}
/* #### Mobile Phones Portrait or Landscape #### */
@media screen and (max-device-width: 640px){
/* some CSS here */
}
/* #### iPhone 4+ Portrait or Landscape #### */
@media screen and (max-device-width: 480px) and (-webkit-min-device-pixel-ratio: 2){
/* some CSS here */
}
/* #### Tablets Portrait or Landscape #### */
@media screen and (min-device-width: 768px) and (max-device-width: 1024px){
/* some CSS here */
}
/* #### Desktops #### */
@media screen and (min-width: 1024px){
/* some CSS here */
}