The factory line guide is generous with the line lengths because it's really hard to make a short rope longer. It's also a bit outdated - from 2010.
"Spun braid" is what used to be supplied with new boats. It was Samson Trophy Braid and looks like this:
Double-braid, Dacron core and cover. Pre-'90s boats were supplied with white; post about 1997, boats were supplied with red.
It has a fuzzy, slightly knobby cover that's great on the hands, but it doesn't move through the blocks well. It also soaks up water. A lot of water.
It's relatively inexpensive (3/8" diam is ~$0.90/ft).
For the past few years, new boats have been supplied with Liros Magic Sheet. It has a Dacron cover over a polypropylene core. The diameter has been reduced from 3/8" (9.5 mm) to 8 or 9 mm. Liros line is not easily obtainable in the US (an internet search only turned up international sellers).
Sta-Set is a very inexpensive, all purpose line.
It tends to have a slick cover when new, but the slickness wears off with use. Because it's a Dacron double-braid, it tends to get hard and stiff with extended exposure to the elements (just like Samson Trophy Braid).
All that being said, the replacement line that most racers use is New England Ropes Salsa, 8mm (a bit bigger than 5/16")
It's a single-braid (no core) of Dyneema and spun polyester (Dacron). Very flexible, very soft on the hands and it doesn't soak up a lot of water. It holds up well, but it's more expensive (about $1.50/ft.).