Generally what would you say is the better fork of these: Manitou, RockShox, or Marzocchi for quality?

All brands will perform well when the correct model is bought, however, there are many personal preferences and beliefs.

Marzocchi's are generally known to last long and be very durable (ex. Marathon series.)
Manitou is generally known for its quality and performance of affordable air forks (ex. Skareb series.)
Rockshox is generally known for producing extremely lightweight forks (SID series.)

It all depends on your budget, riding style, and a few personal preferences. You should rarely make a decision based solely on brand.

Fox............

I concur

marzocchi has long been know as the set and forget fork(maelstrom says this alot, i can personally vouch for this, i have the 888 and ive never had to worry about it at all). rockshox is notorious for blown seals,although i think they have solved this problem). and people like raiyn absolutely despise manitou(eg: manipoo, i think becous of bad CS) and fox is more of the high end novilty fork, very good quality. people like push industries(they rebuild forks and shocks)only rebulid fox stuff because they think "Performance, reliability, innovation, and value are what keep Fox Rear Shox and Front Forx as industry leaders year after year." i very rarely hear anything bad about them (exept recently the cracking arches on the 40rc2, but that problem has been solved)

I've never had an issue with a Rock Shox seal plus they're fairly easy to replace. https://www.enduroforkseals.com/index.htmlIt's not just that. Every Manipoo I've ever ridden was a flexy POS. If you want to talk about seal issues I'd also point you straight at Manipoo.
Some people like them, and even have good luck with them, but that ain't meIt's not so much a novelty as a "Boutique" brand.https://www.pushindustries.com/
They do a darn fine job of it too