The Idea with a compact frame is that by using a, for instance, fifty six cm top tube length, which would usually go with a bike with fifty six cm center to top seat tube, you have a fifty cm center to top measurement. This compact design saves six cm of seat tube(one of the thicker tubes) making the frame lighter and also stiffer(because the triangle is smaller). I like the way my compact bike rides, but I prefer the look of a conventional geometry steel frame. So I have both, but if I could only have one I would have to take the performance advantage of the compact.