For me RENEKTON is better build idk relly bcs i didnt played him that much but lets say frozen mullet sunfire boots for armor or magic resist depends of enemys ravenus hydra randuins omen and blood or spirit visage hope i helped
i think renekton is better especially after nerfs to masteries in i think 4.3 , he can dive mundo on lvl 6 with ignite and jungler's help , i can tell you both builds Renekton:Hydra,sunfire,mercury boots,visage,omen,banshee's/guardian. If they dont have ap you can replace visage with thormail Mundo:sunfire,visage,tabi,omen,banshee's,thormail
Mundo has a durable at teamfights with ultimate. But Renekton, has a sick stun! So in my opinion better is Renekton!
Betther Top Is Rene Rene is betther becaus he have good lifesteal...If he is off tank he is op! Rene build:SunfireCape,BlackClever,Blade Of Ruined King,Ravenus Hydra,Frozen Mallet and Spirit Visage Mundo build:Frozen Mallet,Trinity Force,Blade Of Ruined,Warmog Armor,Spirit Visage,Sunfire
Renekton is better for top. If you face vs champion with good poke on your lane, start with hp regen, hp potion and ward, if you face vs good early damage champion buy cloth armor or doran's shield. You can start with doran's blade too if u want to play aggressive. Try to get brutalizer as fast as you can cause of it cdr and armor pen, then go for Sunfire cape and Ravenous Hydra, then Randuin's Omen and Spirit Visage. For boots take Mercury tread's if their apc is fed or if they have lots of cc or take Ninja tabi if their adc is fed.
Mundo is a tank, Rene is a bruiser! My build for Mundo: Boots Mercury Treads or Ninja Tabi (Depends on enemy team), Spirit Visage, Warmrog, Randui Omen & Guardian Angel. My build for Renekton: Ninja Tabi, Brutalizer (Lategame Black Cleaver), Randuin Omen, Hydra, Spirit Visage or Warmrog (Depends on enemy team)