No one is using both of these currently. The Oura 3 isn’t in the hands of the public yet and a very low % of Whoop users have received their model 4’s.
I’m currently using a whoop 3 and oura 2, and my whoop 4 was shipped today - so I will be able to compare the whoop 4 sometime next week.
I recently posted a very high level summary of my opinion on the oura 2 and whoop 3 here: