Like most publishers we are reluctant to upgrade anything as we all know the risks invloved... but was pleasantly surprised by the new features of version 2.09 - lots of features built in so they have done their homework.
Had a few issues which were addressed by the developers so happy in that regard.
Some people complain about prices of components but lets face it - if you have a commercial site $100 isn't much for a core part of your website...
One ideal feature is the ability to assign a listing to multiple categories, in our case we have wedding suppliers in various categories (ie Photographers, Venues, Cakes etc) and we then able to assiign them to their local region category - perfect for a directory.
There doesn't seem to be a manual but if you can work Joomla you should be able to master Mosets Tree - if not the developers answers questions promptly.
Someone else made the point - of course if joomla.org uses it on this site then it must be good...