Flown with them once (2 legs) and was very happy.
Ground crew and FA stood out being VERY friendly and going out of their way to be helpful, and I think they primarily go for attitude and service skills - the FA/ground crew had a real mix of ages, shapes etc, definitely wasn't selected for single look or hair colour.
EOS appears to have good utilisation - at times colleagues have trouble getting on the flights we want, and my two flights were at about 80%, considering that they are premium only that is a pretty good load factor, so unless they get their pricing completely wrong they will at least cover the direct cost of their flights.
In terms of customer experience: Better than BA club world (which I used to travel a LOT) and a bit below BA first (which I got upgraded to a couple of times), and way above the American transatlantic carriers at a comparable price - our firm policy allows EOS travel and AA business travel as they apparantly cost about the same, and everyone tries to get on EOS.
The biggest risk is a huge downturn in business travel. If the banks force everyone into Economy EOS will have nothing to fall back on, but as you probably have experienced the axe will fall elsewhere, too... Other than that, if they can sustain their pricing there is good demand.
Good Luck!