It's understandable that it's not there where Joomfish is on the 1.5 (e.g. a language switch will bring you always to the frontpage), but it is already pretty powerfull, and just easier to manage as the new joomla multilanguage option.
Also Stephane replied always absolutly quick, to my E-Mails.
and he gave me the Tip to update from Joomla 1.7.2 to 1.7.3, because with the new Joomla language filter plugin you have the opportunity to turn off the default language Code in the url which ist pretty important for seo
Also I got a good and quick support, Markus helped me out with a Problem the same day (displaying an audiofile in the listview).
The Strength is definitely the ease of use compared to other good cck components like seblod though seblod might be more powerfull with the next stable release.