Solid construction -- won't wobble when animal climbs up or down. Some dogs will avoid stairs that have any wobble in them. These definitely don't have that problem.
The wood finish is attractive enough for this to pair with living room furniture, and the carpeting is well attached and seems durable. Very nice that it can be converted from steps to a ramp -- that's a little unusual in stairs that are this nicely finished.
For travel ... The unit is heavy to carry (solid wood construction), but then that's what makes it so stable for animals to climb on. We fold it down and wrap it in a moving blanket to keep it from getting banged up. The 3-step version works very well with some of the taller hotel beds.
These are on the expensive side, but we've been very happy and feel it was money well spent.
The 3-step version fits to many applications that that is what we went for. There is an option to buy a 2-step version for shorter beds, chairs, etc.