VCOLOMBO  I got this app free as part of MacHeist and have found it very useful, however I just checked this page to see what the normal cost is so I could recommend it to some coworkers and WOW! Although I like this app I do not think it's worth nearly $40! For that price I'd much rather simply enter time via the web.

There are also some features I think are missing from this app but they're not show stoppers.  
(Version 2.6.4)

VCOLOMBO  I haven't tried the 2.0 beta but I've been using Jungle Disk for a while now, on both Mac and Linux, and have to say that I've been completely satisfied. I do agree that there should be a way to get rid of the activity window. The developers should take a look at MacFusion (the MacFuse application, not VMware Fusion) for future functionality and UI inspiration.

I do agree that it would be nice if directories and files created by Jungle Disk would be easily manageable with another S3 utility, but since Jungle Disk is cross platform and offers the option of a web UI I haven't had much need to manage my S3 content with anything else.

Jungle Disk is not without its cons but overall I've been very satisfied.  
(Version 2.0b2)