I think most subbers are going off some translators or their defining the word by which context it's in. Like kuso is basically an insult in Japanese so it can mean jerk, bastard etc but it depends on the context of how it's used.

"Kuso" does neither mean jerk or bastard. It means "shit!" or "crap!". If you odd a word describing a person, then it can make it an insult. "kuso baba" for example can mean "old hag".
As for the "jerk"/"bastard"-translation, the word you refer to might be "yarou", which Momotaros uses a lot. Nihon usually translates it as "bastard" or "asshole", which is a bit harsh imho, but not necessarily wrong.

The picture quality is bad, but I wouldn't say it's unwatchable. As for the subs, the mistakes are nothing that would influence your understanding of the story. It's mostly minor stuff, from what I remember. (That being said, I only watch the DVD raws these day for the neat quality, but I understand some Japanes, so it works fine for me.)

W, OOO, Den-O, Ryuki, Black, and of course Gaim are my favourites.

But translating cusses to hardcore swears make it sound more adult, nii-chan!

Fuckin' Nihon.

Well, they do have improved on that matter over the years.

Yeah, they were never that bad with it. You should see some of the old school Dragonball Z fansubs.

Or some Naruto fanlations of the manga.

Top 3 for me..

Ryuki
Hibiki
Faiz

Fourze, W and Gaim I really have trouble ranking against eachother as 4-6. Wizard is my least favorite of what I have seen, but I still enjoyed it.

TOP 5 FOR ME:
1. Den-O
2. Gaim
3. W
4. Fourze
5. Kabuto