I actually think Vader, in his prime and with the Force, is more powerful than Sidious, just like Sidious is better than his master Plagueis. Vader's intensity and focus simply cannot be matched, in my opinion.
However, why did you post this thread if you alreafdy thought you knew the answer? No offense, just wondering.
no sidious would win. maul wouldnt be alive for long at all, then the battle would be with tyrannus, vader and sidious. if this is mechanical vader, hell easily be killed with a little force lightning, if not he may stay alive a bit longer, but eventually he would die. the fight would be between sidious and tyrannus, it would be a good fight, but i think in the end sidious would win, he was the master after all and although tyrannus is a very good duelist, id say sidious' force powers, and dueling skills (which arent really that bad) would allow him to win.
and dipsit, idk if sidious is stronger than plagueis, i mean he did kill him in his sleep, which might prove sidious didnt think he could have taken him in a one on one battle.
Oh, I know. I was just basing my opinion on the fact that Sidious made more of a difference than Plagueis. I should have mentioned that. However, the opinion I expressed was still completely subjective and based on a point of view rather than facts. I didn't mean to sound ignorant - I'll try to explain myself more next time.
I don't know who would win...
Well they are all Sith and all serve under Sidious... They know full well that Sidious is far to powerful for one of them to take alone otherwise they would have done it. So if they are smart they would team up and then take sidious out... I'm not so sure if Maul would join them, but probably...
Sidious has no chance against the three of them and would die under their power.
Then only three remain, Maul Vader and Dooku. If Maul starts fighting Vader then Dooku wins, because he would shoot lightning at Vader who would be unable to block it and would die. If Maul faces Dooku then Vader will win by burying the both of them under god knows what. Constantly attacking them while they were fighting, and then finally after Dooku killed Maul he will take out a weakened Dooku who would probably shoot lightning that could be blocked.
Now that I think about it I have made a description of what would happen.
They would all turn there lightsabers on in an X formation. All four would clash, spin and use force push on whichevers opposite. Darth Maul would stare at Darth Tyranus, Darth Sidious would stare at Darth Vader. DV and DS would clash again and DM would use the same thing he did on Qui-Gon to DT. However, V saw him do it and slice him in 2. And M would be thinking deja-vu.
All three would be staring at eachother then V and S would team up against T. T would be scared. He clashes with them both and then push them away (via LSB). Then S would stay out and it would be V vs. T. They would do lots of cool tricks and V would slice him down the miiddle.
"Very good my apprentice"
"It's not over yet"
"So be it"
V and S would clash a lot and do lots of tricks but then S would use his force lightning and kill him.
By the way this is OT Vader. Incase you're wondering.