The deal is that the beta patch is, in fact, MORE laggy and LESS stable if ANYONE on your server is using dialup. That, and they're beta-releasing it so as we players can tell them any bugs. Q&A testers don't play online with the 10,000 different types of computers out there, so they won't see everything.
If you don;t have dialup, get the beta patch. Its really, really, really much better than the original. Gotta love those tough AIs, and plasmas that are more likely to hit than to miss. Be advised, the fed single player campaign becomes MUCH harder post-patch because of improved romulans.
Alexander