So far, Bush hands-down. The President ignored the war on terrorism almost entirely, started a war on false propaganda (almost all of the "intel" was already proven false by the CIA before Bush, Cheney, et al repeated it over and over again) a war that his admin claimed would be over in 30 days and pay for itself. The President proclaimed socialism and tried to nationalize corporations and gave billions and billions in corp. welfare.
Now if Obama invades Iran and North Korea (again) like some on the right advocate, he would be much worse than Bush