If Revelation is a RL model then I’d choose X-Fusion due to the better damping. Not tried one but all the reviews say its very good.
But if the Rev has a RCT3 damper then its a close call.
I think the Slant uses 34mm chassis and is stiffer than the Rev. So if you want to run the fork at 150 or 160mm or will be riding on tough terrain and doing more than trail centre riding then maybe the Slant is the better choice.
Otherwise if the riding is not going to be hard core then go for which ever one is lightest.
X- fusion forks are internally adjustable for travel, so you should be able to adjust the Slants’ travel down from 160mm to 140mm if required.