Gonna have to go with Crime Syndicate in both scenarios. Some of the Ultimates were weaker than their 616 counterparts (Thor especially) but some were more powerful (Cap).
With the CS, you got evil versions of Flash, Superman, Wonder Woman (that lasso is gonna BFR someone fast) and Green Lantern. Owlman is an evil Batman, nuff said!!
Crime syndicate would totally rip the ultimates apart. not saying the ultimates are pushovers. ulti thor and Hulk will put up a fight but be taken down.. and viciously.. they are sadistic evil versions of superman, wonderwoman, green lantern, flash and batman.. i dont think there will be anything but a brutal and painful result for ultimates. sure ultimates are abit 'ruthless' but nothing next to the CSA.