The Metolius Easy Aider is one of the better single step aiders out there. It is light, easy to adjust, and comfortable to hang out in. That said, we just don't like the single-step aider system. As you can see in the video below, it is possible to aid lead with them. However, we don't think they lead nearly as efficient as a typical aider or aid ladder. They are best suited for cleaning pitches because you can adjust the aiders to the exact height you want them. In addition, they have wide steps that make them comfortable to hang out in at the belay. The fact they come with top straps to keep your feet from coming out is a blessing and a curse. Sure, your feet are less likely to come out. However, often, when cleaning traversing terrain or any terrain, it is nice to be able to easily get your feet in and out of the aiders. With these, it is not easy to do that.
So overall, if you are only cleaning pitches, these might be an ok bet. However, for most aid climbers, we would strongly recommend our Best Buy the Metolius 5 Step Aider or our Editors' Choice the Yates Big Wall Ladder.
There is a similar version of this aider made by Yates called the Yates Speed Stirrup. The Yates is a little heavier and the buckle has its pros and cons. We lean more toward the Metolius version but both are pretty comparable.