This waterfall is definitely not the highest but it is pretty wide and therefore makes a strong impression. Do not pass it without visiting because Urriðafoss is worth it. The place is not so touristic, which makes it attractive.
What we recommend you to do is to stay in one of the local houses near the waterfall. We did it and we could see a pasture with beautiful horses from our windows. You can find an affordable house at Airbnb.
Urriðafoss is located nearby a road, which makes it easily accessible.