Well great, its 'tolerable'
This kinda sounds like Ironforge's "I'm happy when my warcraft 3 maps are rated 3 out of 5" attitude 
I said the
worst examples hit the "tolerable" level.

The best examples can stand up with anything that Japan produces.
And when they get a good director and good cast together, the results can stand toe-to-toe with anything that Japan can produce.
How many people would this good cast have? Like all the 8 competent english voice actors the american anime scene has? On the other hand, Japan has hundreds of talented voice actors. With each year more graduating from actual voice acting schools.
There are far more than eight "competent" actors in the American anime scene; I could probably rattle off at least twenty absolutely top-tier names off the top of my head. I won't deny that Japan has a substantially larger pool of actors to draw from, but we also have a number of people who take great pride in delivering quality performances. And for all the options that Japanese directors have, there's still a massive amount of overlap going on over there, with the same set of top-tier actors playing a large number of main character roles.
Just one example: Shinichiro Watanabe himself has stated that he prefers the English cast of Cowboy Bebop to their Japanese counterparts
That's right, its just one example. And cowboy bebop is far more popular in american then it is in japan anyway. That doesn't really say much at all.
It's the one example I gave, but it's not the only one, and even a single one says a lot. Other series whose creative staffs have spoken favorably of the English dubs are FLCL and Trigun. (In fact, Nightow himself has stated that the characters in the Trigun manga are "actually" speaking English, so the dub's sort of the more official version in that sense.

) Those statements aside, I've also heard people who frequent Japanese fan boards state that many Japanese anime fans express interest in the English versions of their favorite series; in particular, Lucky Star is a show whose English dub received fairly widespread praise. I think that's some fairly strong testimony.
No offense Mongoose but you kinda strike me as the average american anime viewer that watches dubs because japanese sounds so funny and loves NGE, Cowboy bebop, Trigun and Ghost in a shell because those shows aired on american tv at one point (Kinda like 90% of the american anime fanbase only knowning gundam wing and thinking its all that gundam has to offer, just because they saw it on tv once)
No offense, Spoon, but while I did get my start in anime watching series airing on [adult swim] (and still do), that was five years ago, and I'm no neophyte anymore. Take a look through
here, more specifically my
completed list. (Christ, I hate MAL's new design tweak; this whole thing should properly display on a single page.) I've watched a diverse array of titles from multiple decades over the history of anime, a number of which were in Japanese. In fact, I've made my way through 450 episodes and counting of One Piece in subbed form. After all of this, the reason I still prefer watching English dubs is that I find characters to much more relatable on an emotional level when they're speaking in my native language. In addition, the lack of subtitles removes an unwelcome distraction that prevents me from focusing my full attention on the artwork and animation, as the show was originally meant to be viewed. It's simply my informed, personal preference.
(Also, NGE is an utter mess from a structural standpoint. An interesting mess, but a mess nonetheless.

)