I used canola oil in my saws for quite a while. It did work well, was cheaper than petro oil, I felt great about the environmental issues and many other reasons.
My saws were drained and put in storage for about three years. Now that I've fired them up I found that the moving parts of the oil pump didn't rotate and the plastic gear stripped. While stripping the saws down I found the canola sludge very hard to clean. since I had oven cleaner on hand that's what I used to soften the sludge. I think that something like Simple Green may work better but it doesn't make sense to buy even more 'stuff' to have under the kitchen sink.
When I was using the saws routinely there was never a problem with the oil pumps. Over the years I've gotten some old saws that had sat around with oil left in the tank and they worked just fine.
I would still use veggie oil because of the environmental issues alone. Now I am aware of a small shortcoming of leaving the veggie oil in the saw though.
Maybe the store bought veggie bar oil has additives that the grocery store version doesn't. I don't know. Maybe I'll have to keep the saws washed down a bit more to keep the gunk from building up but that really is only cosmetic. In fact, the saws don't have that nasty dirty-oil smell with veggie which is a huge plus.