For flat work, I use these boots and love them, just don't make the mistake I did and get the pretty white ones, as that lasts for about a minute. Dover Saddlery | Equilibrium Stretch and Flex Flatwork Wraps .
For jumping I would use something like this Dover Saddlery | Woof Pro Ultra Front Tendon Boots .
Am not a huge fan of polos as they don't do much and can cause injury if they are not correctly applied. It seems to me that there a few people (at least at my previous barn) who like to use them because they look cool and look like they know what they are doing.
I use Polos for my horses until they are using to wearing shipping boots when I trailer, and when I was in England and they were required for cross country events, which was many years ago, and I imagine the rules have probably changed.