Welcome to the wonderful, seductive world of OTL's!
I'm a dealer for a different brand of OTL amp, but have a lot of respect for the Joules.
On paper at least, the Atma-Sphere OTL amps I sell appear to be a better match for your 4-ohm Dynaudios. The ten grand ballpark MA-1 puts out 140 watts into 8 ohms and 135 watts into 4 ohms . This compares quite favorably with the 100 watts into 8 ohms and 80 watts into 4 ohms of the the Joule Marquis, as well as with the 160 watts and 100 watts respectively for the Grand Marquis. Atma-Sphere also offers a power supply upgrade that is beneficial with low-impedance speakers, such as the Dynaudios.
One additional piece of the puzzle you might want to consider is an autoformer like Paul Speltz's "Zero". Your Dynaudios dip down to 3.1 ohms in the bass region, and that's definitely on the low side for an OTL amp. By stepping up the impedance of the load your OTL amp sees, you'll get a bit better control in the bass region and a bit better dynamics.
Feel free to contact me if you have any questions.
