At the end of August I switched feeds for Octopelle because I wasn't really liking the results that I was seeing with his conditioning and ride results in endurance.  We'd been using Nutrena Perform, but I decided to give Omolene Performance a try instead.  And boy, what a HUGE difference that made!  I haven't regretted switching at all.  We finished our last 50 mile ride of the season yesterday at Jubilee, and he finished incredibly strong with his best time yet.  I'll give Purina products a glowing review any day of the week! 
http://horse.purinamills.com/products/omolene/ECMD2-0032696.aspx