Big chippers are actually safer IMO. Less chainsaw work, less exposure to the feed chute because you're chipping bigger pieces meaning you can push them in from farther away. And 90% of the time, the bigger chipper will be machine fed, at least in my experience, be it via mini or full size loader, crane, or whatever else there is.
And as far as maintenance, big chippers cost less to operate and either equal too or less to maintain if done right, because they're built tougher than the baby chippers and can handle the abuse put on them. Again, that's just been my experience and what others have told me.