I agree with memories completely. Veggie is the toughest team to take in ranked play up to super titan. Veggies have a couple maps They can do well on, but adorables is still usually a better choice on those maps. They have more bad match ups than any other race.
It depends on the map and who your opponent is more than anything else. Adorables will always have a large advantage on reaper. Scaly does really well on peekaboo. Feedback dominates on sharkfood island.
Most players tend do think that adorables have the most favorable odds at getting a good match up in league. There are quite a few scaly players, less feedback players and almost no veggie players. Personally I do just as well with feedback as I do with adorables. I feel that a person should find which race they enjoy the most and learn to play them. You can get to super titan without ever spawning a special.