By the time I asked this question, I was continuing on my research and found out that postgresql would be better for the project but not better for programmers.
For instance as a company (H2B Internet Technologies) when ever we use mysql we use workbench to create our db and we use our own tool called auto console to administrate our database which makes the production for a web site REALLY FAST. But we know that not the programmers choose database but the project choose the database. I mean database should be chosen depending on the needs.
That is why we I think we will going to choose between speed and stability.
Also in my research I could not find any free/opensourse tool to create rdb like workbench or microsofts management studio. I think we will first try to create db in workbench and convert the sql code to postgresql.
Do you know any ?