Where in the world can you so easily park a car, approach the waterfall and see a rainbow and then walk behind the water and see it all from "the other side" ? This was our 2nd time and it's just like a fairy tale type of stop

Similar to Skogafoss I would recommend arriving in the afternoon, or at the very least not first thing in the morning, as this waterfall in particular faces more west than south so you want the sun to hit and bring up the colors, and potential rainbows :)

You need to pay for the parking here, but contrary to most paid parkings around Iceland you actually have a machine that you can pay it with a card, but also can use the website/QR code as well. At least the restrooms are "free " :) I guess the cost of parking does that, at Skogafoss parking is free but restrooms/toilets cost $ :)

There is a nice souvenir store here and even some food with sandwiches/pastries to go

There are several waterfalls at this location. An easy walking path takes you to each one. The largest falls is the closest to the parking lot and restrooms and there is a trail that leads you up and behind the falls. This is something not to be missed if you are able. The path is wet, rocky and slippery. There not rails along the entire path so this is not for the mobility impaired. The experience and view from behind the falls is unique and incredible. You will get wet so be prepared.
This location is worth taking the time to drive to and is also included in many of the tours from Reykjavik.