I like it!
I recently switched from using Quicken on Macintosh to cbb on Linux. I was very dubious at first, but have come to feel more and more comfortable with the program.
The data entry is fast and quite similar to Quicken's. The reporting in cbb is weaker than that in Quicken, but I find that I only used a couple of the reports in Quicken -- reports that I can still get from cbb. The biggest deficiency in cbb is its very primitive graphing capabilities, compared to Quicken.
An open, cross-platform journaling program.
A scientific plotting package.