MySQL gem vs RoR default library

I have Rails v 2.0.2 Ruby v 1.8.6 MySQL db v 5.x

I am confused as to whether we should use the MySQL gem or the RoR default MySQL support library. The consultants that had worked on the initial phase of the project had me remove the gem saying that it is better to use the RoR library, that the gem was necessary in earlier version of Rails. BUT, I get the WARNING below which says the opposite.

Can somebody assert that given the versions of Rails and Ruby I should be using the MySQL gem or NOT?

I have Rails v 2.0.2 Ruby v 1.8.6 MySQL db v 5.x

I am confused as to whether we should use the MySQL gem or the RoR default MySQL support library. The consultants that had worked on the initial phase of the project had me remove the gem saying that it is better to use the RoR library, that the gem was necessary in earlier version of Rails. BUT, I get the WARNING below which says the opposite.

Can somebody assert that given the versions of Rails and Ruby I should be using the MySQL gem or NOT?

------ WARNING: You’re using the Ruby-based MySQL library that ships with Rails. This library is not suited for production. Please install the C- based MySQL library instead (gem install mysql). SQL (0.003382) ------

In my experience the gem is quite a bit faster...

-philip