Hmmmmm, I think each forum has it's pros and cons.
Pros:
1) Caraudio.com
Seems to have more knowledgeable audio enthuiasts
Have more people on and ready to help with your situation (No matter How F^ it is.
2) Ecoustics.com
Has more than just car audio to get help on in more forums
Doesn't seem as quick to flame a user over their setup
Cons:
1) Caraudio.com
Has more USERS therefore has MORE douchebags that think they know everything there is to know about car audio.
Seems to have a lot of users who will jump on the boat of whatever's sailing smooth, even if they haven't tried the product
SERVER IS TOO BUSY AT THE MOMENT is annoying
2) Ecoustics.com
Has fegs like JULIOB who can talk about someone's system like it's crap, but runs LANZAR himself
Is absolutely SLOW AS CHIT to get a response to a question, due to the lack of user activity
For Sale section is a complete joke
Search feature is TERRIBLE
No STICKY topics like Caraudio.com has for things like gain setting, test tones, etc...
Overall, I have learned a lot more about the caraudio industry here on Caraudio.com. I found out about this website through ecoustics, and I now rarely post on ecoustics due to the slowness of the forums. I am not trying to say one is better than the other, but simply breaking it down as I see it.
Also, each forum has a ton more Pros, as I just wanted to give a synopsis of what I have seen from both sites.