1)
2) I don't think the Oberth has ever demonstrated the ability to "zip" anywhere. With her tiny engines, she's probably like the Nova, slow as molasses, best employed on longterm studies like the ones we saw in TNG (hanging around a dying star, hanging around the Black Cluster, hanging around a dull gas giant, etc.). Onscreen, an Oberth never spearheaded the push into the unknown.
Timo Saloniemi
I can't remember anything mentioned about the speed of an Oberth, I guess to me it just looks quite fast, as for the rest, well Grissom was the first Starfleet and IIRC only starship orbiting/being around the Genesis planet so maybe she DOES spearhead into the unknown now and then.
