I'm sure the Bryston does just fine. But you can get more is all...
I sure can:
http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php
ESLs are Power Paradigm technology. This is because their impedance curve is not based on a driver in a box with a resonant peak, instead it is based on a capacitor. So the Voltage rules don't work so well- the typical response is not enough bass and too much highs. Also due to the impedance curve you need a really powerful transistor amp to keep up with a less powerful tube amp. The bass region of the speaker is about 30 ohms, so if you have a 600-watt transistor amp it will make about 150 watts in the bass region, which allows a 150-watt tube amp to do the same work, only without the brightness (even though still being extended in the highs).
This is something that was not around 25 years ago- while we had the tubes/transistors debate back then, there was zero discussion about the underlying reasons about how the two technologies interacted with the speaker. Everything was couched in Voltage parlance, which was insufficient to explain what was going on.