Right now my favorite unit is the connection, because even if it is one of the ugliest unit, it is very powerful and versatile. It can act as a tank single handly soaking heavy damage, as a determined killer with its instahit arced lightning shot, and as a teleport to instantly spawn your entire packet army, then recall it before a counter-attack. The fact that it's slow and short ranged makes it even more fearsome, as that way I know my enemies have time to see it coming and so get their fear level rise before all their punit bits blow out. Beside it's not that much as problem since it can simply project a packet squad ahead when needed.
For exemple,
in this video at the 5:00 marks note how a single connection is attacked by a bug army, then summon a packet herd while trashing some bug with its mighty arced lightning, then ends up victorious. And at 6:20, it's probably the same connection that leads a successful assault on a socket. From 8:25 to 9:30 you can also see a lone connection reaching the innermost of the enemy base, but it mostly cruise along, striking there and here, but never teleport packets, so it's not as interesting.