Caedus takes sabers, force either way possibly Plagueis, all out either way
__________________ "Happiness is a lie. Life is horror. The light is always dying all across the universe. The last star will flicker out someday, when it does, all that remains is shadow. And I will be its king!"'-Amahl Farouk
If it's Force only, I'd give a slight edge to Caedus. They're both very academic Force-users and they both have a lot of skills that aren't really that useful in combat. Caedus though is a little more creative and is of the Skywalker bloodline, so he should have the higher upper limit, at least theoretically.
Probably agreed. He's got a similar tanky-ness to him, largely due to his physiology and his ability to retask biological systems. On top of that, he's even more of a physical monster; no less fast, and definitely stronger. Sure, he's not as consummately skilled or varied in his tactics as Jacen, but he's definitely got a solid enough base mastery to keep up with opponents on the Palpatine-tier by his peak.
Regardless, Plagueis' power isn't in his ability to weild a lightsaber anyway, that's more of a defensive practice if anything by his peak. The main advantage Plagueis has over Caedus is his sheer power and knowledge of the dark side; I imagine he would attempt to fight in a similar fashion to Talzin or Vitiate. Then again, this is a strong point for Jacen too; he's got high-end Skywalker tier power, and a pretty diverse knowledge of the Force in his own right.
Could go either way, to be honest, but my money's on Plagueis if he can really go toe to toe with TPM Palpatine like Luceno says.