I guess I should visit here more often, as I just found this thread. Here's my two cents worth on some of what's been discussed.
1.) If you're using a good subwoofer then I would personally choose the Continuum. If, on the other hand, you are wanting a small speaker to play by itself as a near-field monitor then I would personally choose the Piccolo. It has a very similar response curve to the Continuum but is more extended in its vented form. For desk-top use right in front of me, again, I'd personally go with Sopranos. They don't get the love they deserve but they are a very good little speaker. These are my personal choices of what I would use for myself based on these designs.
2.) You can't compare those distortion curves above on the Eclipse woofer and SB' woofers without knowing the exact set-up. When distortion is displayed is terms of harmonic dB below the fundamental it loses its context. If one set of data was taken at 100 dB and another at 90 dB then the distortion profiles will be very different and they are not apples to apples for comparison. You can not tell from this data if the Eclipse is better or worse than the SB's.
3.) Having worked with all of these woofers the Eclipse is the most robust of the bunch and puts out some excellent bass. Better than the SB drivers in my opinion.
4.) The LS3/5a does not have much of a rising treble, it's pretty flat. Here's how the Continuum compares with the 1978 Rogers' LS3/5a measured under very similar conditions:
5.) The RS28a is a very smooth but detailed sounding tweeter. I like it a lot better than the RS28f and better than any other metal dome I have used. It really doesn't do much wrong and it doesn't have a "metal sound", whatever that is.
6.) The Continuum remains the lowest distortion small stand-mounted loudspeaker I have ever designed. I believe the construction of the cabinet has a lot to do with it, but the driver's themselves are very low distortion in their operating ranges as well. (I only qualified this because I have designed some large systems using pro-sound drivers that have more output at the two watts than the Continuum can hit at full volume, so distortion comparisons here may not be fair.)