DEIBEL  Despite (or because of? ;-) its "focussed" feature set, I use Mail Act-On all the time, making my emailing experience more productive. The new version works fine.   
(Version 2.0)

DEIBEL  I am a daily user of Daylite since about a year. All in all I am very pleased with the software. Of course, in the recent months two major hurdles, in integration of synchronisation as well as the Leopard upgrade had to be overcome. After the appearance of the 3.6 betas, and now the final version, I must say that Marketcircle did rather well. Also, the support appears to be pretty responsive and helpful.

Some features could be improved though. The report generator is a good start, but not easy to get used to. I personally prefer to alter the report templates by hand, and am pretty happy with the outcome (e.g., sorting tasks by status: open tasks first, cancelled tasks last). A certain project hierarchy (project with subprojects) would be nice. Drag and drop of Daylite notes should IMO result in an export of the notes title+contents, not the title only. And so on. However, I can live with these issues. I assume that the Daylite developers will have more time now to focus on ease-of-use etc, and am looking forward to future versions of this very useful and well-performing product.  
(Version 3.6)