I have used jForce from 1.5 version, and when my clients wanted to upgrade to joomla 1.7 and later 2.5. I had to get jForce with.
It has been a long way :-) and there have been problems, for some time support was almost none exiting.
But they have changed, many of the problems have been removed and the problem with lack of support especial. Over the last two weeks the Jforce team have been great, working on finding and fixing the problems on my clients site.
I would gladly recommend jForce to anyone!!
It has been easy to work with and also to expand on