When I purchased my copy of Red Dead Redemption, it came with a code that allowed me to get a deed for a unique horse...the "Warhorse". How does it compare with the other horses in the game, specifically the better ones such as the Hungarian Half-Bred, etc?
Comparing to the better horses only, it beats the Kentucky Saddler in nearly all aspects (can't confirm speed). However, in terms of stamina the Hungarian Half-Bred wins and in terms of speed the American Standardbred wins. So overall a great horse but NOT hands down the best for you, try the other top horses to see if they fit your play-style better.
For reference: http://reddead.wikia.com/wiki/War_Horse, wikis are great for this kind of info in case you didn't already check.