Franko, IMO Winuae is most useful when used as an RTG amiga. If you want to run 24 bit graphics software, 3d rendering then winuae has the biggest bang for your buck.
BUT if you want to run stuff that runs on the native chipsets then Winuae just "feels" wrong. This includes most games (but 3D FPS's run faster).
Running a Dpaint/Brilliance/PPAint, animations, a Scala presentation, a demo, a game or viewing some of the hand-drawn art on a 1084 with a good screen just looks so much better than when viewing it in winuae. There's something about the vibrancy of the colors, the blending of the pixels (probably due to the bell curve light distribution of the monitor pixels), the smoothness of the animation.
So for mine, if you want to run software that runs on the chipset, then nothing beats the real thing. If you want to run Amiga software that uses RTG or you need brute CPU speed for then winuae is cheaper and easier to acquire.