With the reminder widget you can't create entries but you can show them and also tick them off, so it's great to show your daily stuff which you do frequently.
The OmniFocus widget shows entries, but you can also create entries directly on the NC. Additionally you can also set an activator gesture to create an entry from everywhere, also lockscreen.
It's recommendable to set bigger and more important tasks here which should be ticked off accidentally.
Both widgets allow you to tap on the entries to get to the respective entry. (This feature is already implemented in the OmniFocus widget, but will we only available with the next update of the OmniFocus app for iPhone for version 2)
you can also just work with one of them, but I really like it to separate projects tasks and daily/routine stuff
