php4beta stable enough for a production server ?

Just a silly question : I know that php4 is in *beta*, but there are probably already people using it on production servers, that's why I'm asking :) Is php4b2 stable enough to be run on a server with a lot of trafic and domains, or should I really wait more ? What kind of problems usually happens with the beta2 ? I'd really like to have php4 for its speed, and because of the sessions funktions. Thanks for your comments, Olivier