We have one at work. We built it out of formed concrete with concrete steps. If I had to do it again I would get a pool contractor to do it.
I think it would be less dollars. We put a 4x4 angle iron along the edge.
We have a rolling oil pan for oil changes. The pit is great for inspections and oil
Changes, but limited in other areas ie a transmission jack won't work.
We have painted the edges safety yellow and have a chain with removable post.
Falling in is a big risk. More likely a visitor than those around it daily.
Some have butterfly doors and some have rolling hatches.
It takes up a whole bay and unless you do a lot of oil changes, probably not ideal.
The money spent on a pit could almost equal a full lift and less lost floor space.
South of the border they use exterior drive up ramps that are about 4 feet tall and each ramp is about 2 feet wide with a space in between.(there probably some in the US, but not as visible) easier to built off a hill side.