For someone who loves Merb and had decided to leave Rails behind (as much as possible), I have very mixed feelings about this. If this means Rails will start to feel more like Merb, fantastic! Otherwise?
I have a feeling it'll be a long while before I really know how to feel about this...
It'll be interesting to see how well this merger actually works in practice. It seems like when large companies merge the results are often underwhelming. Can a merger of large open source projects work? Will the different cultures clash?