Erm, nope. In SW lore, Palpatine is the ultimate Sith; thus, he beats Revan hands down. It's George Lucas' story, so he has the final say in it. And, he says Darth Sidious is the strongest Sith Lord ever.
Hard to imagine if you see how easily Mace Windu did beat him. Without that stupid Anakin interfering he would have been dead way before the original trilogy. :P
However, when it comes up to Sidious vs Vitiate I have to say that Vitiate is way more powerful. He consumes whole planets while Sidious is just a tricky ***hole.