Of all the various pets a wolf has the greatest Patk. The problem is keeping the fragile things alive. However as a Swordsinger you will have the hate skill so maintaining aggro shouldn't be too difficult. Just try and steer clear of ranged mobs and ones that have aoe attacks. Ranged mobs have an annoying tendency to switch target a lot and any aoe attack that hits you and the pet will most likely kill the pet.
well, you want to level a pet and sell it?
the market for pets isent very big, about 0.
but if you want the pet for the roleplay, or help for grinding, go for it :)