As someone who has been using Storm, this looks very interesting. What I particularly like are the clean, well thought-out ideas. Also, easily reconfigurable (at runtime) topologies are something we'd be interested in. I will definitely take a very close look at Onyx.

Performance is important: in our case, decreasing it significantly below Storm's level would not be acceptable.

Also, I watched the Strange Loop presentation and the tree model looks limiting to me: I have topologies where I need to merge information from two streams (but perhaps I haven't understood the Onyx model yet).