I use a Wahl Super Micro trimmer; be warned though, it's still not powerful enough to cut through the most difficult of hair. I need to give a quick chop with scissors to get the worst of the length off, then buzz it. I have found using the bare blade, I can get a very neat bum trim by putting my finger up against the blade (no risk of cutting, don't worry).
I know my vet (same as where @BossHogg gets his trims) uses Oster professional-grade clippers (similar to this one). They cut through hair like butter, but are very expensive!
In an attempt to keep Ronnie from eating the pigs pellets, I rigged up a door for the bottom level with a hole just big enough for the pigs to get in and out. I then screwed in hooks to hang a grill to. Not only would it stop Ronnie, it would keep the pigs safe from passing cats - WRONG!
He crawled in on his belly, then crawled up the ramp to get to the food! Back to the drawing board!