Good. I like O'Malley's skillset, he has some great striking and from what we saw in the Yan fight, his grappling is good.
I feel like he either snipes Merab early I'm the fight or Merab overwhelms him with relentless grappling.
We've heard of volume strikers before but I think Merab is the first fighter to accurately be described as a volume grappler in that his grappling is not successful due to the duration of control ala Khabib, but the sheer number of grappling sequences, even if short lived, that he can initiate with his opponent. The only way to stop him is to finish him or be a good enough striker and grappler to punish him on the feet and either stuff his TD attempts or get back up quickly if taken down AND have 25 minutes of cardio.