PHP Abstraction Layer - Your Opinion Please

Hi,

I am currently looking for PHP database access abstraction layer which
supports PostgreSQL.

The choices are:
1) adodb
2) metabase
3) MDB - merge of PEAR and metabase
4) PEAR only

I would be very glad if you will share your own experience, either good
or bad, with all pros and cons.

Thanks in advance.