I like both of these plants but I honestly prefer the Parsnip.

Guacodile:

Is able to shoot from a distance.

Eats zombies in one lane once the zombie eats them.Can work on land and water but is more effective on land.

I plant the Guacodile in the water and seems to be versatile.

Parsnip:

Is a short range plant.

Once eaten, the Parsnip will 'snip' the zombies in one lane.