The key thing to look for when trying to see how two tracks compare to each other in terms of level of competition is purse sizes.
The majority of people know that the NY circuit is significantly more difficult than the PA circuit. This is due to NY tracks offering more purse money for the same type of race. For example, a $14,000 claiming race at NY's Belmont Park, will typically have a purse size of roughly $28,000. While on the other hand a $15,000 claiming race at PA's Penn National, will typically have a purse size of about $19,000. Naturally, due to the added monetary reward, better horses are lured to tracks with higher purse values.
Another quick way to get an idea for the level of race track is to look at the type of races that are offered, the more maiden, claiming, and maiden claiming races you see, typically the lower the class of race course. The very elite race courses will have few claiming races and many more maiden special weight, allowance, and stakes races. The role of an owner is to look at these different tracks and run their horses where they have the best chance to win for the most purse money possible.