I loved the Gen 3 contests... once I figured out I was supposed to give PokeBlocks to my mons. But in the Master Rank it was difficult even then to win the primary judging. There was one time I had a Sealeo in a Master Rank contest, possibly a Beauty one, anyway, this Electrode named "Rodlect" got several 'hearts' from the audience, and then Sealeo was put on the pedestal in all his Gen 3 sad-eyes-sprite glory... and received no hearts. It was truly a sad moment to behold!
I have won the Master Rank Beauty contest with a Milotic in Emerald I think. Was likely wearing a Blue Scarf. That was probably the only way it managed to get enough votes in the primary judging.
Winning the contests in Gen 6 was far easier, because there was no limit of how many PokeBlocks a Pokemon could eat. You didn't need to be conservative about it, and that also meant that one Pokemon could ace all the categories. I at least got to enjoy having five of my Pokemon displayed in that upper floor of Lilycove Art Museum, something I never managed in Gen 3. But I missed the old way of making PokeBlocks. I play Gen 3 a lot still anyway.
The Super Contests of Gen 4 were okay. But Poffins were quite annoying to make after the relative simplicity of the PokeBlock Blender. Oh, and I always love when the "Blend Master" appears in Emerald. Him and his supply of rare berries... and impossible precision!