hey there ! I switch off between the two actually! *MOST* of the time its embark (shows the time in a big box) but if I have a lot of things I need to do I’ll switch on momentum (the one that says “hello _______) because momentum allows you to have a task checklist which I find rlly helpful. If you’re looking for functionality I would definitely go for momentum! The only real reason I don’t use it is because it can get a bit overwhelming in my opinion. It has A LOT of features, most of which can be edited down so that you only have to see what you want, but with embark I just get the date and time and its a lot less busy. From what I’ve seen, the extension Clarity seems to be a healthy mix of the two, but i’ve never used it myself. 
As for other extensions i’ve tried out, Focus is really great one if you prefer to look at your week as a whole rather than go day by day. You set up a weekly timeline and within each day you have a task list where you can rank your tasks which is really cool.
I’ve also tried Lanes, which in my opinion is really underrated. Lanes gives you the opportunity to create multiple task lists in a day, color code those task lists, and complete each task list using a built in pomodoro timer customized to your liking (i.e. i want to work on x list in x minute sessions with x minute breaks) its all around super nice and i’m actually kinda shocked its a free extension. Those are the only ones i’ve personally tried and would recommend, but here is a masterpost that has a LOT of recommendations for extensions organized by what they are best for.  

My apologies for this being so wordy, but I do hope it helped! Thanks so much for asking me things, it actually makes me so happy oml!!