I primarily use mysql however the past 6 months i've been developing in mssql. So i need support for both.

I thought about dbx but looks like pdo is the db abstraction layer from php.net

PDO ships with PHP 5.1, and is available as a PECL extension for PHP 5.0; PDO requires the new OO features in the core of PHP 5, and so will not run with earlier versions of PHP.

Note: This extension has been moved to the PECL repository and is no longer bundled with PHP as of PHP 5.1.0.

Then there is adodb which my current application extensively uses.
Problem is i wished it used exceptions.
And i originally got it because it had caching ability.. bad reason for me to choose it.
known to slow the application

The there is
Propel which most new php frameworks use with Creole

Which i've never used.

is pdo a good choice?

note: version is not a problem i host my own sites and have full control over everything.