Italian marque founded in 1945 that also owns Piaggio and Moto Guzzi, generally more reliable than Ducati and Cagiva but less so that the Japanese competition. From 2004 when the 2nd generation of RSV and Tuono 1000 were released reliability was improved to near Japanese levels making their motorcycles a much more attractive proposition on the used market.
The smaller 2-strokes such as the RS125 and RS250 are still to be avoided unless you are a real enthusiast. The Japanese 2-strokes although older are generally more reliable except those produced by Kawasaki.
Max Biaggi has had the most success racing Aprilias winning 3 250cc titles from 1994 – 1996 and 2 World Superbike championships in 2010 and 2012 aboard the RSV4.
GP legend Valentino Rossi won world 125 GP championship aboard an Aprilia in 1997 and current Moto gp champion Jorge Lorenzo dominated 250′s in 2006 and 2007 winning both titles for Aprilia also.