I've done a bit more testing and I am not quite so happy with blubox. The original test I did was with b/w jpegs and they looked fine. But colour jpegs show that blubox doesnt return the files to their original quality. Zooming in shows differences in colour which results in noisy looking photos. Raw files dont compress, which doesnt surprise me, and I dont suppose I would want to anyway as they are basically my negatives. Tiff compressed down to an amazingly small size. A 3.6Mb compressed down to 85kb, thats about 3% of the original size, but not without suffering loss of quality too.
I guess this is a pretty good bit of software for sending lots of jpegs if you are not too worried about a bit of loss in quality (but remember, the recipient needs a copy of blubox too). But its not much use for archiving which is what I had in mind. I wont be buying the full version.
I really only deal with tiff images, i've found that for tiff's by changing the compression setting to Lossless i still get great compression and the images come back extactly the same size and quality.
I've still found it a great way to share a lots of jpegs, when i'm sending photos to friends and family i prefer to be able to send a lot more in a shorter space of time, even if i lose a very small amount of quality.