Is MariaDB a suitable drop in replacement for MySQL on a standard LAMP stack?

Question

I've been wondering lately what (if any) are the improvements available in MariaDB over 'conventional' MySQL?

I understand that where platform interoperability and/or backwards compatibility may be an issue then sticking with the tried and trusted MySQL is best. But for a stand-alone DB on a stand-alone web site/application are there any benefits to be had by using Maria?

Will Maria work with common web platforms such as WordPress, Drupal, Joomla etc.?

I expect that some of this is going to come down to choice/preference of storage engines, but to be honest I still don't know half the time if/when I should use MyISAM, InnoDB or any of the others! Which is better or faster or whatever?

The only thing I get is that if I want 'true' table relationships (i.e. foreign keys etc.) I use InnoDB.

Thanks for any help or clarity people can offer me.