would be very interested in experiences too, since we plan to install this extensions on all our production servers..
as far as i know there should be no problems using this extension along with popular byte-code caches like APC and eaccelerator but there are problems with some other extensions like ionCube and others (http://blog.php-security.org/archives/53-Trusted-Zend-Extensions.html).
Also want to hear expiriences from others about suhosin/eZ combination! I hope I'll try this soon on our development server... It would be also cool to measure the speed difference.
I've just installed eZ publish 3.8.6 on a server running suhosin extension (apache 2.0 + mod_security + php 4.4.4 + suhosin 0.9.6 + eaccelerator 0.9.5)...