I would judge any and all platforms on the level of support provided for live, 100% hands-off automated trading.
To me, the most important thing is the ability for a live traded strategy to recover from a loss of connectivity, and/or a plain restart, without losing track of its positions and open orders.
From the list, I only have experience with Ninja, and from that operations side of things it lacks the following:
- a public API to reload historical data from the strategy (there is one, but it is undocumented, and really hard spot even using Reflection)
- an embedded mechanism to restart a strategy from its last know position and open-orders (this is all left to to programmer to do)