DiabloScott hit the nail on the head. Both companies had issues at times.
Klein was the first US manufacturer of AL frames in the modern era around 1978. I believe Motobicane was the first to offer a Vitus AL bike in the US in 1982. The Moto got extremely bad reviews in Bicycling Magazine. They called it the rubber bike although that same bike had won almost ever classic in europe. Alan bikes were somewhere in the mix also but never popular. Klein offered a unique product that was almost a piece of art & was very impressive at least in the years before C'dale. Kleins were very expensive compared to even established top of the line bikes. In 1985 C'dale began selling cheep Al frames. The quality was also cheep if compared to a Klein. They road like an I-beam but you could get a C'dale at almost any price range. Price is everything. By say 1990 Cannondale had improved the product to the point it was very good. Klein began producing more economical models also but they were always perceived as an expensive perhaps overpriced bike.