I love both shows and will gladly recommend either (along with DEH - for me, DEH is my cathartic release, Great Comet leaves me in awe, and CFA is my feel good show) this season.
I usually bring up Great Comet with a disclaimer - I think there's a slight risk going into it because the myriad of styles both musically and in how things are staged (especially the club and opera) are definitely not going to be to everyone's liking and for those who don't like it, it tends to be a strong opinion. However, the reward pays off handsomely if you end up enjoying the spectacle. It really is quite unlike anything else currently on Broadway, and Josh Groban is fantastic as Pierre.
On the other hand, Come From Away unexpectedly stole my heart. Great Comet is a roller coaster ride because you never quite know what's coming next, while Come From Away is a roller coaster of a different sort due to the seamless pacing and you get swept up in the ride. It's smaller in scale and only one act, but that doesn't diminish the emotional impact.
Based on the other shows you're seeing plus mention of Josh Groban, I'd suggest Great Comet out of the two, but if a coworker were to ask me for a show to blindly recommend to a visiting family member, I'd tell them Come From Away, if that makes sense.