Found this on the bobcat site, it was on a pdf of the units specs, (Motor oil is not an acceptable alternative fluid). This answers the question. Will be using only Bobcat hydraulic fluid and not using the neighbour's attachments. thanks
Standard oil works just fine, they just say that so you buy their oil. They add a few extra things to reduce wear. They only ever used 15W40 in the older machinesw before they started recommending the bobcat fluid.
Being a new machine, it is a way that if something was to fail, they can say no warranty as you didn't use our oil. I run engine oil in my machines, always have. They never missed a beat.
It's hard when you want to use an attachment, even if it was rented from a deaeler. You never know what they were on before, so you may get non bobcat oil in your machine anyway. I wonder how that would go with bobcat warranty....