I gather you refer to Y STR tests (Short Tandem Repeat), which measure the length of a fragment of DNA, not specific base pairs. The autosomal DNA test uses an entirely method, which does look at specific base pairs. If you are interested only in your straight paternal line, the Y STRs are a very good approach, and FTDNA (as mentioned above) is considered the best company for that type of test. It can measure as many as 111 STRs.
However, autosomal DNA doesn't blend like paint. It's more like mixing red and yellow jelly beans than red and yellow Jello. The DNA is chopped up with each generation, but the pieces retain their identity and can sometimes be traced to a specific ancestor (with luck and hard work). If you're hoping to find a match who knows more about your brick wall than you do, the autosomal DNA might identify such a cousin from any line of descent. These animations show how that works:http://www.smgf.org/pages/animations.jspx