Very nice how you make this video self-contained by explaining things when you mention them instead of linking to a previous video. That said, I don't foresee wanting to use either of these effects with my play style.
Roar of Time bonuses feels too good to not be used along with crazy events (such as the x4 XP). Being able to pause the timer for up to 2 hours alone is insane. As for Spacial Rend, it doesn't feel as rewarding as what Roar of Time offers in my opinion, but it definitely has its own usage. Personally, I'd lean more towards Roar of Time. It could very well come in handy for me, especially since I'm 2 levels away from reaching level 50 😅