I was a previously a user of FacileForms, and migrating my apps to BreezingForms and joomla 1.5 was a "breeze" (well, sort of!!)
No real issues whilst migrating, and also provided me with the opportunity of tidying up the code in my old FF's!!
Summary, excellent component, and those people waiting to migrate their FF's to Joomla 1.5 and BF, don't be scared...just do it!!