This is the 3rd Unibit of this size in the last 10 years that I have owned, it is not that it is poorly made, its just that I keep using them.  This is the only bit that I have found that I can cut gasket foil, if I do not have a punch that size (requires some trickery).  It has many, many uses and I keep finding new ones.  I have tried other brands but in this style, of the major brands, this last the longest of the non-impact tapered bits.  I have run it at 7,500 rpm without incident and as slow as 2 rpm on 1/8" titanium sheet (prepunched starter hole).  The Unibits may seem expensive when compared to HF or other cheap brands but with these you get quality and service life.