I've never used an Oster, so can't rec, but everyone that has one loves it.
I personally have Andis & Wahl clippers. Love both, super quiet & works great.
My Andis is the kind where different blades are used. It's not clunky or heavy. Here's a thread about it:
http://www.yorkietalk.com/forums/yor...room-home.html
My Wahl is the kind where it has 5 blades in 1. It's cordless, super quiet & very light. I use this one the most, it's perfect for trimming their paws, tipping ears, sanitary trims. It also comes w/plastic combs that you can use to trim their body. I personally have not used the combs, so can't give any reviews on it.
Wahl Arco Pro Purple Pet Cordless Clipper Kit at Blain's Farm & Fleet
Wahl also makes another cordless clipper called Bravura.