Hello Chingi,
I have experience with EA Studio since the time it was launched(before that was only FSB Pro).
I can say that EA Studio is a must in algorithmic trading. I have about 5 years of experience in EAs, and I divide it all on two periods.
First was the time when I started to try coding EAs and buying EAs which were expensive. Never ended with a good result.
Second is when I found FSB Pro and EA Studio later on. Put my things together. Tested EAs for nearly year before going to live accounts, and saved some money. Now for the last one year I do this full time, so I can say that EA Studio and FSB Pro changed my life a lot!
I do not have a boss over my head, I do not have working time, I take holidays whenever I decide, and most important I have time for my family now!
So, how satisfied I am with EA Studio, from 1 to 100, definitely 101 :)