I think he is potentially stronger, although when you consider he had to use Kyuubi to even work his way to a lesser loss, then it might be closer than some think. But they can't exactly lose or anything though.
Madara will win 100%. For so many reasons,
1 he lived for so many years and grew old
2 he practise so many justu with his ems and reginna and hard a lot of time to practise with hashirama wood, he also read all the uchiha tablets.
OT: obito stated while talking to sakuke that madara had an usual Chakra among the uchiha's.