Tentionmaru will be much more efficient at close quarters, so Thanos' advantage would be to spam ranged attacks. Honestly leaning towards Tentionmaru on this one. Power and Space stones suck by themselves and tossing meteors won't faze Tentionmaru.
Even soul or mind aside, reality is op as hell and time is on a somewhat the same level. I was thinking about complete IG Thanos and Full Power Tentionmaru with prior knowledge (you know, for Tention to stop hand movements), but desided to do this instead.
Yeah, Thanos with just the Power and Space Stones can't really do much. He's got an AP advantage, but almost everything he does will get easily dodged. Couple that with the fact that Tention dominates in close quarters combat, and Thanos is done for.