I can't speak for the packaging of the other two companies since I've never ordered from them. The rodents from CBC were double-bagged, and the sealable bags were the thick, heavy plastic like you would normally use for metal parts that have sharp edges that could puncture or slice the bag open. Also removing just one or two rodents from the bag was easy; sometimes removing a few is difficult because the rodent tails get wrapped around each other, or the rodents are damp and then stick together once frozen.
The feeder weights were well within the advertised range, without all being at the low end or high end. They were intact, no signs of injuries/illness/mange/sores/growths/etc., and they smelled like rat but not rat urine or rotting rat like you can get when the bags thaw and are re-frozen.