I really like the concept, I really dislike the lock-in. I think what I want is the unholy love-child of Saleae and Dangerous Prototypes[1]. I've got the original version of DP's Logic Sniffer [2] and built a really nice USB 2.0 protocol analyzer with it. The combination of open source, inexpensive hardware, and awesome documentation let me take it in a direction that no one else had. Salea on the other hand has really slick software that is sexy as heck, but only runs on Windows and well, I am really trying hard to not have to have a Windows box around on my workbench.
[1] http://dangerousprototypes.com/
[2] http://www.seeedstudio.com/depot/preorder-open-workbench-log...