Honestly, Polish to me are an easy competition if you live in a smaller area and have good (non-hatchery) stock, simply because few people have good Polish. Of course, the bigger the show, the more Polish breeders, but otherwise. . .
But, in general, Polish are a nice show breed, but again you'd need to do a lot of research with getting the right stock. They're not very easy to find, especially online. Your chances are good with White Crested Blue, Black, and Chocolate - But on colors like Gold Laced, Silver Laced, Black, and White, especially in LF form - Quite hard to find. Now for bantams, they're a lot easier to find.