I made the switch after reading all the licensing info on Mysql's site and all the posts involved. It
seemed much safer than having to worry about getting a commercial
license from mysql for internal applications or ones that face
customers. Did not need the hassle. I have found postgresql to be very
good so far. And there is no quibbling on the licensing of it.
What possible quibble could you have over the MySQL license?
From http://www.mysql.com/company/legal/licensing/ :
For those developing open source applications, the Open Source License allows you to offer your software
under an open source / free software license to all who wish
to use, modify, and distribute it freely.
The Open Source License allows you to use the software at
no charge under the condition that if you use MySQL in an
application you redistribute, the complete source code for
your application must be available and freely redistributable
under reasonable conditions. MySQL AB bases its interpretation
of the GPL on the Free Software Foundation's Frequently Asked
Questions.
MySQL also offers a commercial license that lacks the source-distribution condition. You get to choose which one you use.
(The following opinions may lack legal insight.)
Having to freely redistribute your source may be an issue; is that what troubled you? This is just the condition that all GPLed code imposes. Of course, that's why people sometimes prefer the Apache, MIT or LPGL types of license.
You could always distribute your application without MySQL, thus avoiding all licensing issues altogether. Your customers are perfectly free to download the SQL of their choice to use with your app. (If your customers must acquire MySQL itself then you are stuck with either GPLing your code or getting the commercial license.)
As far as I can tell, you don't need the commercial license to deploy your product and charge for the service thus rendered, only in order to redistribute MySQL without GPLing your software package.
OTOH, the MySQL pro license is only about $600 (U.S.) retail. If $600 is going to make or break your business then you might want to revisit your business plan, or bring in more outside investment.
IMO, there's absolutely nothing in the MySQL license to give PostgreSQL the edge. I would have to make such a decision entirely on technical grounds.
