Quoted from Jediturtle:

Love mine. It makes the job much easier and safer, but be warned that it still isn't "easy". There is a learning curve and you still need some decent muscle to use it. I am a pretty small guy...5'6" 150 lb-ish and definitely not a body builder. Each time the feet grab a step, the center of gravity changes dramatically and it wants to catapult me up and over the pin. You definitely have to be holding on and braced for the force. I have gotten used to it and really do not have a problem doing it, but it's not like you can just push the button and have it do all the work. You also have to be careful about the angle and making sure the feet stay on the edge. The lifting feet are very small, and if you have it tilted back too far, they can come off the step. It takes a bit of practice to get the hang of it, and the first stair going down still give me a seriously butt pucker. None of this is a deal breaker, and I'm not trying to scare you off of it...just things to be aware of to avoid surprises. I would say it's one of the best pin related purchases I've made and it's saved my back many times over.
I have the big wheels, and find them to be a necessity. It makes getting over door frames, carpet, etc so easy. Plus if you are moving it far, the pin can rest of all 4 wheels and be moved with very little effort. I bring mine to MGC set-up each year because of this and it's a life saver.
I kind of wish I would have sprung for the fork lift to make getting in and out of vehicles easier. I can still handle them myself, but that would be nice. For leg set-up, I have a modified tipping hydraulic table which is super handy.
It is heavy, but not to the point of being hard to deal with. I put mine in and out of my vehicle myself with no problem. I wouldn't want to carry it around, but have no problem lifting it when needed. Mine is the 60" though...the bigger ones I'm sure are beefier.

Quoted from flipnout1:

If used correctly this will not happen. As with any tool there is a right way and a wrong way to use it.
This happened because he lowered the Escalera down slightly. This allowed the belts on the sides to contact the edge of the step and once the lifting feet came off the lower step all the weight was transferred to the belts. Not on the lifting feet as designed. The weight is supposed to all be on the lifting feet. So the belts did what they were designed to do and allowed the Escalera to slide down. Obviously not the intended reaction. If you keep the Escalera at the "balance point" of the load THIS WILL NOT HAPPEN. The result was the load slipped on the belts down the stairs. New users, and in this case an experienced user, are afraid that the load will go forward and will tend to lower the handles to prevent this and the result will be exactly what happened here. Maintaining the balance point is key to prevent this from happening.
As others have said practice. Try what I described with just the Escalera and you will see exactly how this happened.
Larry