Traditional lines: tapered and furled, these are very easy to cast and quick to setup. Length is fixed. Good to begin with.
Level lines: are good alternatives for casting against wind or fishing larger streams. Coming in spools of 65 ft, these lines can also be cut to the desired length and will yield a couple of lines of different lengths. #3.5 thinner, more challenging to cast but easier to keep off the water. #4.5 heavier, so easier to cast, slightly more challenging to keep off the water.