right - not mauser based.
the difference between them are going to seem minor at first, until you handle a couple.
other than push or controlled feeds, and assuming similiar stock comparisons, look at the safeties... much difference there. and even the ones w/ 2-position safeties (savage, remington), they are markedly different in looks. check out the wood used for the stocks. do you like shiny finishes (700 bdl, browning), or matte finishes (ruger, winchester)? do you not care how the stock looks?
how about the bolt? note the knobs on the bolts... quite different in looks and feel. also, how far do you have to rotate the bolt to open it (browning has a very short throw)...
for a rifle for someone starting out who either doesn't know, care, or who hasn't developed a discriminating taste, yeah, they are all essentially the same.