It usually takes about 30 seconds of streaming to reach RoM's main menu and character creation interface. Also of note is the fact that the browser version runs on the same servers as the client version, so you'll still have access to all of your friends and familiars.
The bad news is that the browser version is only available in Europe as of today. We'll update you as soon as we hear about Frogster's plans for additional markets.
[Source: Frogster press release]