I have used them a couple of times, machines were placed on pallets.

The safest way would be to have the machine wrapped then strapped down arse first onto the pallet.  Reduces the risk of the machine falling off.

I know of machines that have been dropped and basically flat packed itself.  Horrible to see photos of this.  Unfortunately I don't think any amount of bubble wrap will protect a 150kg machine being dropped from the back of a truck.

Like anything in life you get what you pay for.  Last machine I spent around $500.00 getting shipped from NSW.  Was worth the extra money and was well looked after.