I got the free Camtasia 3 deal posted here a while back....and while it has more features than BB Flashback, I much prefer BB Flashback. So I purchased it (well technically my company purchased it). In my opinion, it's just a more intuitive, more polished, less confusing app to use compared to Camtasia. The features that I felt were really missing in BB Flashback v 1.5 were added in 2.0 (fade in/out transition of callouts and ability to add hotlinks to web urls). So while I had a free app in Camtasia....I ended up springing for the $100 (after DC Discount) on BB Flashback. Actually, my company ended up paying...but you get the idea. I have yet to provide feedback to BB on 2.0 beta but I only found a couple of small issues with it (fade in/out issue with low frame rate recordings and serious increase in filesize (like 4 to 5 x the file size) when zoom/pan is introduced).
Also, I liked that when I purchased the BB Flashback full version....they continued to offer me the (DC Member) half price discount that came with my lite version purchased a year before. Overall....I've yet to be disappointed with this app. That said, test drive it first (and Camtasia) since it doesn't have every feature Camtasia has. And while those extra features may not be important to me, they may be deal breakers to you.